Abstract:
An image display method comprises uploading images from a terminal of users to a server via a network, storing the images uploaded by the users in the server, calculating a value of the stored images, displaying a predetermined number of images among the stored images at the terminal in a manner in accordance with the value of the images.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based upon and claims the benefit of priority from prior Japanese Patent Applications No. 2011-074927, filed Mar. 30, 2011; No. 2011-115509, filed May 24, 2011; and No. 2011-185627, filed Aug. 29, 2011, the entire contents of all of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an image display method and an image display system in which a server and a terminal are connected via a network to display an image stored in the server. 
         [0004]    2. Description of the Related Art 
         [0005]    In recent years, how to enjoy photos has diversified with widespread use of digital cameras. 
         [0006]    Various kinds of image processing are enabled by making good use of properties of digital image data. 
         [0007]    For example, a technology capable of displaying a video similar to an ordered artwork is proposed (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 8-44867). In this publication, a technique used to produce the ordered artwork is simulated. An automatic video processing is performed so as to produce video having a preferred appearance of ordered artwork and comfortable to consumers desiring decorative artworks. A corrected video is derived by lowering precision of the original video. The corrected video is added to the original video. 
         [0008]    Also, a technology that takes an entire original image into consideration to make a conversion into a painting image of high artistic quality by developing the technology of Jpn. Pat. Appln. KOKAI Publication No. 8-44867 is proposed (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 2004-213598). Color information and characteristics such as brush touch information are extracted from images of paintings actually drawn by painters. The extracted characteristics are added to a shot image. 
         [0009]    Also, a technology allowing a selection of various images by changing the shape of an element figure, which is the unit of transfer, or the density or order of points on which transfer processing is performed is proposed (see, for example, Jpn. Pat. Appln. KOKOKU Publication No. 1-046905). 
         [0010]    A powerful image processing engine is needed to make such image conversions and thus, installing an image processing engine on a server in a network to allow a user to upload a photo of the user to the server for image processing such as a snapshot-to-painting conversion on the server can be considered. 
         [0011]    In such a case, if the user produces an artwork by snapshot-to-painting conversion of the user&#39;s photo, he (she) wants to show the artwork to others. One method of satisfying such a desire is posting a photo on a network by a social network service (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 2008-242639). 
         [0012]    An image obtained after a photo of a user being uploaded to a server by the user and image processing such as a snapshot-to-painting conversion being performed thereon will be called an “artwork” below. 
         [0013]    If many users post a large quantity of artworks on a server, the number of artworks that can be displayed at a time is limited and a problem of deteriorating properties of browsing such arts is caused. 
       BRIEF SUMMARY OF THE INVENTION 
       [0014]    An object of the present invention is to provide an image display method, a server, and an image display system that display an image stored in the server via a network efficiently so as to attract attention of users. 
         [0015]    According to the invention, an image display method comprises uploading images from a terminal of users to a server via a network; storing the images uploaded by the users in the server; calculating a value of the stored images; displaying a predetermined number of images among the stored images at the terminal in a manner in accordance with the value of the images. 
         [0016]    According to the present invention, the images stored in the server can be displayed efficiently so as to attract attention of users. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0017]      FIG. 1  is a block diagram showing the configuration of a network of an image display system according to embodiments. 
           [0018]      FIG. 2  is a block diagram showing an outline configuration of a server of the embodiments. 
           [0019]      FIG. 3  is a diagram showing an example of attribute information of a user ID. 
           [0020]      FIG. 4  is a diagram showing an example of attribute information of an image ID. 
           [0021]      FIG. 5  is a flow chart to exchange data between a terminal and the server. 
           [0022]      FIG. 6  is a flow chart illustrating snapshot-to-painting conversion on the server. 
           [0023]      FIG. 7  is a flow chart illustrating face detection in the snapshot-to-painting conversion. 
           [0024]      FIG. 8  is a diagram illustrating creation of a face region. 
           [0025]      FIGS. 9A ,  9 B, and  9 C are diagrams illustrating an importance map. 
           [0026]      FIG. 10  is a diagram illustrating a boundary of the face region. 
           [0027]      FIG. 11  is a flow chart showing processing concerning a download of an artwork on the server. 
           [0028]      FIG. 12  is a flow chart showing screen display processing when the server displays many artworks at a glance in the first embodiment. 
           [0029]      FIG. 13  is a flow chart showing page arrangement processing on the server. 
           [0030]      FIG. 14  is a diagram showing an example of a display screen when the server shows many artworks at a glance. 
           [0031]      FIG. 15  is a flow chart showing image display processing when the server displays many artworks at a glance in the second embodiment. 
           [0032]      FIG. 16  is a flow chart showing page display processing on the server. 
           [0033]      FIGS. 17A ,  17 B, and  17 C are diagrams illustrating a time line display of a plurality of artworks by the server. 
           [0034]      FIG. 18  is a flow chart showing a modification of the second embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0035]    The embodiments of the present invention will be described below with reference to drawings. 
       First Embodiment 
       [0036]      FIG. 1  is a block diagram showing the configuration of a network of an image display system common to all embodiments of the present invention. A server  10  with a social network service function is located at an image service site. A plurality of terminals  1 - 1 ,  1 - 2 ,  1 - 3 , . . . are connected to the server  10  via a network such as an Internet  500 . The terminal may be an ordinary personal computer or mobile phone. 
         [0037]    The server  10  stores image data (mainly image data of a photo shot by a digital camera) uploaded from a user via the terminals  1 - 1 ,  1 - 2 ,  1 - 3 , . . . , converts the uploaded image into painting image, and also allows other users to browse the uploaded image and the converted painting image. 
         [0038]      FIG. 2  is a block diagram showing principal portions in the configuration of the server  10 . The server  10  is provided with a member area  100 , a common area  200 , and a control area  300 . 
         [0039]    The member area  100  is an area provided for each registered member and stores a user ID  102  to identify each member and various kinds of attribute information  104  for each user corresponding thereto. 
         [0040]    The attribute information  104  is, as shown in  FIG. 3 , user-specific information including the name, handle name, gender, age, region, membership type, and others. The membership type includes a free member registered without charge, a pay member registered on a chargeable basis, and a premium member who pays a special membership fee (for example, an annual membership fee). 
         [0041]    The member area  100  includes an uploaded image memory  106  which stores image data of photos uploaded by the user, an artwork memory  108  which stores painting images (artworks) obtained through snapshot-to-painting conversion by the server  10 , and a downloaded artwork memory  110  which stores artworks of other users downloaded from the other users. 
         [0042]    The common area  200  is an area provided commonly to all users and includes an artwork area  202  which stores many artworks obtained by snapshot-to-painting conversion of images uploaded by the users. 
         [0043]    Each artwork stored in the artwork area  202  has image data  208  stored together with an image ID  204  to identify the artwork and attribute information  206  of the artwork. 
         [0044]    The attribute information  206  includes, as shown in  FIG. 4 , the user ID indicating a contributor of the artwork, date information such as the creation date or posting date, size of image data, image type information such as the type of painting tone, access count information indicating the number of times the artwork is browsed, download count information indicating the number of times the artwork is downloaded, point information indicating evaluation of the artwork, and other information specific to artworks. The creator of the artwork is known from the user ID and whether the creator is a pay member or premium member can be identified. 
         [0045]    In the present embodiment, artworks are not displayed uniformly and instead, the display manner can be changed based on the “value” thereof. Examples of the value include the point number, which is attribute information attached to each artwork, access count, and download count, and the membership type of the creator of each artwork. 
         [0046]    The control area  300  includes a snapshot-to-painting conversion processor  302 , a parameter table  304 , an importance map  306 , a display controller  308 , an evaluation controller  310 , and a membership management unit  312 . 
         [0047]    The snapshot-to-painting conversion processor  302  performs snapshot-to-painting conversion processing that converts image data stored in the artwork memory  108  into painting image data. The parameter table  304  stores parameters for snapshot-to-painting conversion referenced by the snapshot-to-painting conversion processor  302  to perform the snapshot-to-painting conversion processing. The display controller  308  stores a control program that causes a screen to display artworks. 
         [0048]    The evaluation controller  310  evaluates artworks stored in the artwork memory  108  of the member area  100  based on the access count or the like and attaches a point to each artwork. The membership management unit  312  manages members based on the user ID and controls services separately for free members, pay members, and premium members. The membership management unit  312  also administers the social network service function of the server  10 . 
         [0049]    The server  10  is provided with a CPU  20  and a display buffer  30 . The CPU  20  controls the whole server  10  (each unit described above) and also performs various kinds of processing needed to display many artworks at a glance on the Internet. 
         [0050]    The CPU  20  also includes a graphic accelerator  22  to perform advanced graphic processing. As the graphic accelerator  22 , for example, the NVIDIA GeForce (registered trademark) series, ATi RADEON (registered trademark), or open GL and extended libraries to use the open GL may be adopted. 
         [0051]    The graphic accelerator  22  enables the time line display in which images are caused to display like a flow over time by specifying only some conditions from driver software. Generally in video editing, the time line display is a function to manage the flow of a whole artwork in a time sequence and in Twitter (registered trademark), the time line display refers to tweets posted by users and displayed in the order of time sequence, but the time line display herein means displaying the flow of the whole artwork by changing the flow over time. 
         [0052]    The display buffer  30  is a work memory to generate images for the display when the CPU  20  causes a display screen to display many artworks at a glance. 
         [0053]    Concrete operations of an image display system according to the present embodiment will be described below with reference to flow charts. 
         [0054]    First, processes when an image is uploaded, displayed, browsed, and downloaded between the terminals  1 - 1 ,  1 - 2 ,  1 - 3 , . . . and the server  10  on an image service site will be described with reference to  FIG. 5 . 
         [0055]    If the user is a member (a free member, pay member, or premium member), the user accesses the server  10  from the terminal of the user (step SB 1 ). The server  10  authenticates the user ID after the user being logged in (step SC 1 ) and, if it is verified that the user is a member, sends a page of the member so that the user can view the page (step SC 2 ). 
         [0056]    When the page of the member is opened, the member uploads an image (step SB 2 ). The uploaded image is stored in the uploaded image memory  106  of the member area  100  of the server. If the member request a snapshot-to-painting conversion of the image (step SB 3 ), the server  10  performs the snapshot-to-painting conversion processing (or pictorial conversion processing) (step SC 3 ) and the converted image, that is, the artwork is stored in the artwork memory  108 . 
         [0057]    The member may personally enjoy the converted artwork, but may post the artwork if the artwork is desired to be released to other users (step SB 4 ). The posted artwork is transferred from the artwork memory  108  of the member area  100  to the artwork area  202  of the common area  200  and stored there. Incidentally, the attribute information  206  as described with reference to  FIG. 4  is attached each artwork in the artwork area  202 . 
         [0058]    The server  10  displays artworks in the artwork area  202  at a glance if necessary (step SC 4 ). Incidentally, the server  10  resizes artworks in the artwork area  202  when displaying artworks at a glance if appropriate. That is, because the size of artworks in the artwork area  202  is normally larger than the image size for display at a glance, the artworks are reduced and if the size of artworks in the artwork area  202  is smaller than the image size for display at a glance, the artworks are enlarged. 
         [0059]    The member can browse any artwork displayed at a glance in an actual size by making a request of browsing (step SB 5 ). If a browsing request is made, the server  10  displays the requested artwork in the actual size (step SC 5 ) and also adds up a point to the artwork whose browsing is requested (step SC 6 ). 
         [0060]    The member may press a GOOD button displayed in the page of the member and indicating that the browsed artwork suits his (her) taste or write a comment such as his (her) impressions (step SB 6 ). If the GOOD button is pressed or a comment such as impressions is written, the server  10  adds up a point to the browsed artwork (step SC 6 ). The evaluation of the artwork is thereby raised. It is assumed that the point number of comment writing is higher than the point number of the GOOD button. 
         [0061]    The member can also request a download of a browsed artwork (step SB 7 ). If a download request is made by a member, the server  10  permits the download if necessary (step SC 7 ) and the member can download a browsed artwork only if the download is permitted (step SB 8 ). The downloaded artwork is stored in the downloaded artwork memory  110  of the member area  100 . 
         [0062]    If a download request is made, the server  10  also adds up a point to the artwork (step SC 8 ). 
         [0063]    On the other hand, other users other than members, that is, any user can browse artwork stored in the artwork area  202  of the common area  200  in a state of the display at a glance by appropriately accessing the server  10  (step SA 1 ). Further, any user can also browse any artwork displayed at a glance in the actual size by making a request of browsing (step SA 2 ). 
         [0064]    Then, if any user presses the GOOD button because the browsed artworks suits his (her) taste (step SA 3 ), the server  10  also adds up a point to the browsed artwork (step SC 6 ). 
         [0065]    Next, the technology of snapshot-to-painting conversion processing when the server  10  converts uploaded image data into a painting image will be described. 
         [0066]    The snapshot-to-painting conversion is an image processing technology to convert each pixel constituting an original image such as a photo to an artwork according to predetermined parameters (snapshot-to-painting conversion parameters). The artwork includes an oil painting, thick oil painting, gothic oil painting, fauvist oil paining, water color painting, gouache painting, pastel painting, color pencil sketch, pointilism, silkscreen, drawing, and air brush. 
         [0067]    The technology of snapshot-to-painting conversion image processing converts an original image to an image looking like a painting basically by automatically adjusting/combining parameters of various kinds of effect processing known as photo retouch software. 
         [0068]    Effect processing includes, for example, texture processing that provides a special texture by mapping the texture to an image and resolution processing that increases the texture and resolution by dividing an image into a contour portion, a texture portion such as a fine pattern, and a flat portion and performing appropriate processing on each portion. The effect processing also includes HSV processing that adjusts the color by dividing the color into three elements of the hue, saturation, and value, RGB processing that adjusts the degree of each color of R(red), G(green), and B(blue), and RGB substitution processing that makes a substitution in the direction of R to G, G to B, and B to R. The effect processing also includes an edge extraction processing that applies a filter called a Laplacian filter and an intermediate density extraction processing that applies a filter called a median filter. The effect processing also includes a density extraction processing that performs processing when a histogram in RGB of adjacent pixels is extracted to extract minimum/intermediate/maximum densities, an equalize processing that corrects the contrast or enlarges an image&#39;s histogram by setting the darkest portion of an image as black, the brightest portion as white, and appropriately distributing a histogram therebetween, a gamma correction processing that adjusts an intermediate brightness while maintaining a bright portion and a dark portion, and a shadow processing that brightens a dark portion of an image or darkens a bright portion thereof. The effect processing also includes a solarization processing that when the RGB value of each pixel is brighter than a threshold, inverts the RGB value thereof and a noise addition processing that adjusts the quantity and color of noise by randomly drawing dots to cause noise. 
         [0069]    The effect processing also includes an effect processing called HDR (High Dynamic Range) in which a photo with a wide dynamic range that cannot be expressed by an ordinary photo is compressed into a narrow dynamic range width through tone mapping to correct whiteout due to overexposure and black crushing due to underexposure so that power of expression is increased. By applying this effect processing, an image realizing a new photo expression that brings a photo closer to memories or impressions a person&#39;s brain has received and adds an artistic expression can be obtained. 
         [0070]    That is, the snapshot-to-painting conversion processing is in principle a kind of effect processing and a snapshot-to-painting conversion algorithm creates various kinds of painting tone by appropriately combining effect processing and parameters and is programmed as the snapshot-to-painting conversion processing. 
         [0071]    In the conversion algorithm, a parameter group P, which is a set of the parameters to convert pixels of an original image, is prepared in advance. If there are 12 kinds of painting tones, parameter groups are represented as P 1  to P 12 . How to determine parameters also changes the tone of a converted image. If the parameter group for the conversion into an oil painting tone is P 1  and there are m parameters in P 1  needed for effect processing to convert an image so as to look like a painting tone image, the parameter group P 1  contains a plurality of parameters P 1   1  to P 1   m . 
         [0072]    The snapshot-to-painting conversion algorithm described above in detail is stored in the snapshot-to-painting conversion processor  302  of the control area  300  of the server  10  and parameter groups are similarly stored in the parameter table  304  of the control area  300 . 
         [0073]      FIG. 6  is a flow chart for performing snapshot-to-painting conversion processing by the snapshot-to-painting conversion processor  302  of the server  10 . As shown in  FIG. 6 , the snapshot-to-painting conversion processor  302  first performs pre-processing (step SC 101 ). This step is processing performed commonly regardless of the type of painting tone. The effect processing described above is performed on each pixel and thus, image data needs to be in bitmap format. Thus, image data normally in JPEG format is converted into the bitmap format. 
         [0074]    In addition, uploaded image data has various sizes and thus, the snapshot-to-painting conversion processor  302  resizes the image data to the number of pixels in the display area, for example, 800×600 pixels. A large image is reduced and a small image is enlarged. This is because if the size is determined, parameters only need to be fixed and processing is more efficient. Needless to say, when a snapshot-to-painting conversion of an original image described later is made, the snapshot-to-painting conversion occurs in the size in which image data is uploaded. 
         [0075]    Next, the snapshot-to-painting conversion processor  302  performs face detection processing to determine whether the photo to be converted contains any face (step SC 102 ). This is because if an extreme conversion of a face portion is made, the converted image may be unnatural and thus, particularly finer snapshot-to-painting conversion processing is performed on the face portion. 
         [0076]    In the face detection processing, as will be described later by using the flow chart in  FIG. 7 , importance changes even in an image between a face region and the background or between a center portion and a peripheral portion and thus, importance map data is created for the image and stored in the importance map  306  of the control area  300 . 
         [0077]    Subsequently, the snapshot-to-painting conversion processor  302  causes the user to select the desired painting tone from the oil painting, thick oil painting, gothic oil painting, fauvist oil paining, water color painting, gouache painting, pastel painting, color pencil sketch, pointilism, silkscreen, drawing, and air brush (step SC 103 ). 
         [0078]    If the painting tone is selected, the snapshot-to-painting conversion processor  302  proceeds to the flow of each painting tone conversion algorithm. If, for example, the oil painting tone is selected, the snapshot-to-painting conversion processor  302  proceeds to step SC 104  and if the watercolor painting tone is selected, the snapshot-to-painting conversion processor  302  proceeds to step SC 105 . Otherwise, the snapshot-to-painting conversion processor  302  proceeds to the flow of other painting tone conversion algorithms (step SC 106 ). Incidentally, when executing each algorithm, the snapshot-to-painting conversion processor  302  references the parameter table  304  and the importance map  306  of the control area  300  (steps SC 107 , SC 108 , SC 109 , SC 110 ). 
         [0079]    In the processing in steps SC 104 , SC 105 , SC 106 , the snapshot-to-painting conversion processor  302  makes a snapshot-to-painting conversion intended for image data of the display screen size. If a decision is instructed from the terminal  1 - 1  of the user (step SC 112 : YES), proceeds to the snapshot-to-painting conversion of the original image (step SC 113 ) and, if redoing in another painting tone is instructed (step SC 112 : NO), returns to the processing in step SC 103 . 
         [0080]    For the snapshot-to-painting conversion of the original image in step SC 113 , the snapshot-to-painting conversion processor  302  performs painting tone conversion processing on the original image based on the painting tone conversion algorithm determined in step SC 112  while referencing the parameter table  304  and the importance map  306  (steps SC 114 , SC 115 ). If the image sizes are different, appropriate parameters are different even if the painting tone is the same and thus, the parameter table used in step SC 115  is different from parameters used in step SC 107  or SC 108 . 
         [0081]    Then, the snapshot-to-painting conversion processor  302  performs post-processing to convert the converted original image back to the JPEG format (step SC 116 ). 
         [0082]    Subsequently, if any person&#39;s face is successfully detected in the photo to be converted in the face detection processing in step SC 102  (step SC 117 : YES), the snapshot-to-painting conversion processor  302  causes the evaluation controller  310  to add up a point to each of the creator of the artwork and the artwork (step SC 118 ). 
         [0083]    Next, the face detection processing in step SC 102  by the snapshot-to-painting conversion processor  302  described above and a procedure for creating an importance map will be described with reference to  FIGS. 7 to 10 . 
         [0084]    In the face detection processing, as shown in  FIG. 7 , the snapshot-to-painting conversion processor  302  first analyzes the target image data to determine whether there is any face therein (step SC 151 ). Any known face detection technology can be used and thus, a detailed description thereof is omitted. In the face detection processing, even if a face is detected, it is difficult to accurately extract the contour thereof and thus, the snapshot-to-painting conversion processor  302  sets an elliptic or rectangular region containing a face region to the image data (step SC 152 ). 
         [0085]      FIG. 8  is a diagram illustrating a region containing a face region. A rectangular region “sq” contains a face F 1  and an elliptic region “e 1 ” contains the face F 1 . 
         [0086]    Then, the snapshot-to-painting conversion processor  302  creates an importance map (step SC 153 ).  FIGS. 9A to 9C  are diagrams illustrating the importance map. In the processing in step SC 153 , if the snapshot-to-painting conversion processor  302  detects faces F 1 , F 2 , F 3  from image data as shown in  FIG. 9A , the snapshot-to-painting conversion processor  302  sets face regions sq 1 , sq 2 , sq 3  as shown in  FIG. 9B  to the image data. 
         [0087]      FIG. 9C  is an important map  306  showing the importance of regions set to the image data. In the processing in step SC 153 , the snapshot-to-painting conversion processor  302  first sets the first importance level to regions E 1 , E 2 , E 3  of the face regions sq 1 , sq 2 , sq 3 . Next, the snapshot-to-painting conversion processor  302  sets the second importance level to a region E 4  in the center indicated by an ellipse e 13 . Further, the snapshot-to-painting conversion processor  302  sets the third importance level to a region E 5  in a background portion indicated by an ellipse e 14 . Lastly, the snapshot-to-painting conversion processor  302  sets the lowest importance level to a peripheral portion E 6 . 
         [0088]    That is, each region E 1  to E 6  and information indicating the importance level set to each region E 1  to E 6  shown in  FIG. 9C  become an importance map. 
         [0089]    Then, when performing snapshot-to-painting conversion processing on each pixel of image data, the snapshot-to-painting conversion processor  302  makes a finer snapshot-to-painting conversion on a region of increasing importance level and a more coarse snapshot-to-painting conversion on a region of decreasing importance level. As a result, the snapshot-to-painting conversion of the region E 6  of the peripheral portion whose importance level is the lowest becomes somewhat blurred. Needless to say, this is only an example and it is also possible not to apply the snapshot-to-painting conversion processing to the face regions E 1 , E 2 , E 3  so that the atmosphere of the faces is not damaged. 
         [0090]    If the importance level is denoted by α(x, y)(α has the same number of pixels as image data), conversion operations of a pixel A are given by: 
         [0000]        A   RGB ( x,y )= A   RGB ( x,y )× P   1 ×α( x,y )
 
         [0000]        A   RGB ( x,y )= A   RGB ( x,y )× P   2 ×α( x,y )
 
         [0000]        A   RGB ( x,y )= A   RGB ( x,y )× P   m ×α( x,y )
 
         [0091]    Where (x, y) denotes two-dimensional coordinates and A RGB  denotes three components R, G, B of the pixel A. That is, the importance level of the parameters P 1 , P 2 , . . . , P m  changes depending on the value of α. 
         [0092]    Incidentally, instead of providing the importance level α for the same number of pixels as image data, only six kinds of importance data may be prepared by setting the same importance level to each area of E 1  to E 6 . Instead of only six kinds, overlapping areas may be a little more fragmented by setting an intermediate value of importance. 
         [0093]      FIG. 10  shows further fragmentation of the region of the contour portion of the face region shown in  FIG. 8 . If the importance level is changed inside and outside the contour of the face region, a difference in conversion may arise in a converted painting image and thus, as illustrated in  FIG. 10 , the importance level set to the peripheral region of the face region is increased (decreased) in the order of sq&gt;e 1 &gt;e 15 . In this manner, the snapshot-to-painting conversion of the contour portion of the face can be made stepwise in a more natural way. 
         [0094]    Next, the operation of the server  10  when the user downloads an optional artwork will be described. Incidentally, membership registration is needed to download an artwork. 
         [0095]      FIG. 11  is a flow chart showing processing concerning a download of an artwork on the server  10 . The processing in  FIG. 11  is performed by the CPU  20  of the server  10 , the evaluation controller  310 , and the membership management unit  312 . 
         [0096]    If the artwork desired by a member to download is specified on the server  10  (step SC 201 ), the membership management unit  312  determines whether the user is a pay member (here, an ordinary pay member or a premium member) or a free member (step SC 202 ). If the user is a pay member, immediately proceeds to step SC 207  described later. 
         [0097]    On the other hand, the user is a free member, the membership management unit  312  reads the point corresponding to the evaluation of the artwork from the attribute information  206  of the artwork (step SC 203 ) and also reads the point held by the member who is about to download from the attribute information thereof (step SC 204 ). 
         [0098]    Next, the membership management unit  312  calculates a payment point from the balance of the point (corresponding to the evaluation) of the artwork and the point held by the member (step SC 205 ). If the payment point is sufficient, the membership management unit  312  proceeds to step SC 207 . But if the payment point is insufficient, the artwork cannot be downloaded and the membership management unit  312  returns to step SC 201  to cause the user to select another artwork. 
         [0099]    Then, on the server  10 , the CPU  20  reads the artwork specified by the user from the artwork memory  108  of another user who is the creator of the artwork (step SC 207 ) and the evaluation controller  310  adds up a point to each of the creator of the artwork and the artwork (step SC 208 ). That is, things are arranged for members (free members, pay members, and premium members) so that the evaluation of artworks rises with an increasing number of downloads of members&#39; artworks and also a point is added to the point area in the attribute information of the user ID  206  of the member who is the creator, which increases the points held by the member. 
         [0100]    Then, on the server  10 , the CPU  20  performs download processing that stores the artwork, read in step SC 207  in the downloaded artwork memory  110  of the user who has requested the download thereof (step SC 209 ). 
         [0101]    Next, the operation of the server  10  when artworks in the artwork area  202  are displayed at a glance will be described.  FIG. 12  is a flow chart showing screen display processing performed by the CPU  20  when artworks in the artwork area  202  are displayed at a glance. The screen display processing is the processing corresponding to the display processing at a glance (SC 4 ) in the process shown in  FIG. 5  and is the processing that causes the screen of the terminal  1 - 1  of the user accessing the server  10  to display many artworks represented by image data. 
         [0102]    In the screen display processing, as shown in  FIG. 12 , the CPU  20  first reads a plurality of artworks to be displayed from the artwork area  202  and performs page arrangement processing that arranges the image data in predetermined positions inside the display buffer  30  in a predetermined size (step SC 301 ). Details of the page arrangement processing will be described later. 
         [0103]    Then, the CPU  20  displays at a glance the artworks arranged in the display buffer  30  in a state shown in  FIG. 14  (step SC 302 ). In the present embodiment, as shown in  FIG. 14 , a plurality of artworks to be displayed is displayed on one screen in an arrangement state in which the direction of the horizontal axis is set as the type of painting tone and the direction of the vertical axis is set in order of date (the top line is the latest). 
         [0104]    If page feeding is instructed from the user (reader) while the artworks are displayed at a glance (step SC 303 : YES), the CPU  20  changes the artworks being displayed in units of pages by the page arrangement processing in step SC 301 . 
         [0105]    If scrolling is instructed from the user (step SC 304 : YES), the CPU  20  scrolls the artworks being displayed in the vertical direction or the horizontal direction by the page arrangement processing in step SC 301 . In the present embodiment, the scrolling directions that can be instructed by the user are both the left and right directions in the horizontal direction, but only the downward direction in the vertical direction. 
         [0106]    Further, if one of the artworks being displayed is selected by the user while the artworks is displayed at a glance (step SC 305 : YES), the CPU  20  reads image data of the artwork from the artwork area  202  (step SC 306 ) and enlarges and displays the artwork (step SC 307 ). The present processing is processing that causes the screen of the terminal  1 - 1  of the user accessing the server  10  to display the artwork in the actual size. 
         [0107]    The CPU  20  continues to display artworks at a glance by returning to step SC 302  until the end of the display at a glance is instructed from the user (step SC 308 : NO) and when the end of the display at a glance is instructed (step SC 308 : YES), the CPU  20  terminates the screen display processing. 
         [0108]    Next, content of the page arrangement processing performed by the CPU  20  in step SC 301  will concretely be described according to the flow chart in  FIG. 13 . 
         [0109]    In the page arrangement processing, if the processing timing thereof is, for example, when the screen display processing is started or page feeding is instructed from the user and when scrolling is not instructed from the user (step SC 351 : NO), the CPU  20  performs the processing below. 
         [0110]    First, the CPU  20  clears the display buffer  30  (step SC 352 ) and then reads image data of artworks to be displayed from image data (JPEG data) of many artworks stored in the artwork area  202  into a work memory in order of date (step SC 353 ). Incidentally, the size of artworks to be displayed may not be fixed. The work memory is a memory area for artwork secured in the memory region of the display buffer  30  separately from a memory area for display. 
         [0111]    Next, the CPU  20  checks the value of artworks whose image data has been read (step SC 354 ). 
         [0112]    The value includes, as described above, the point number, access count, download count, and the membership type of the creator of each artwork which are attribute information attached to each artwork. Here, for convenience of description, the value of each artwork is defined as a point number obtained by multiplying the point number of each artwork by a multiplying factor in accordance with the membership type. The multiplying factor in accordance with the membership type is, for example, 1 if the creator of the artwork is a free member, 2 if the creator is a pay member, and 3 if the creator is a premium member. 
         [0113]    Subsequently, the CPU  20  determines the display size of artworks in accordance with the value (step SC 355 ). When determining the display size, the CPU  20  relatively increases the display size for an artwork with increasing value. 
         [0114]    In the processing, for example, the minimum display size and the maximum display size used as reference are predetermined. Then, the multiplying factor proportional to the value of an artwork is determined by a predetermined formula and the display size in accordance with the value of the artwork is calculated by multiplying the minimum display size by the multiplying factor. Then, if the calculated display size is equal to or less than the maximum display size, the display size is determined as the display size of the artwork and if the calculated display size exceeds the maximum display size, the maximum display size is determined as the display size of the artwork. 
         [0115]    For example, several display sizes such as large, medium, and small are preset and the value of artworks is also divided into several levels such as high, medium, and low to determine on the display size of each artwork corresponding to the value level of the artwork. In any case, the display size of a valuable artwork is enlarged and the display size of a less valuable artwork is reduced. 
         [0116]    Next, the CPU  20  sets the image data read in step SC 353  into the display buffer  30  as bitmap data of the display size determined as described above (step SC 356 ). More specifically, the CPU  20  determines basic conditions for drawing the bitmap data in the display buffer  30  by the graphic accelerator  22  and sets the conditions to the graphic accelerator  22  via a driver software. 
         [0117]    Subsequently, the CPU  20  determines whether the artwork to be displayed is an artwork of a pay member or a premium member. If the artwork to be displayed is an artwork of a free member (step SC 357 : NO), immediately proceeds to processing in step SC 360  described later. 
         [0118]    On the other hand, if the artwork to be displayed is an artwork of a pay member or a premium member (step SC 357 : YES), the CPU  20  selects the type of display frame in accordance with the membership type (step SC 358 ). Then, the CPU  20  synthesizes the determined type of display frame into the image data to be displayed in bitmap format (step SC 359 ). 
         [0119]    In the present embodiment, two types of display frame, the display frame for pay members and the display frame for premium members are prepared as the display frames and one of the display frames is selected in step SC 358 . The display frame is intended to make artworks highlighted and is image data representing a pattern to decorate artworks like a picture frame. Moreover, the display frame for premium members is differentiated so as to cause, for example, a sense of higher quality than the display frame for pay members. 
         [0120]    Next, the CPU  20  determines whether free space to arrange new artworks in the column in accordance with the painting tone of artworks to be displayed is available in the display buffer  30  (step SC 360 ). In the present embodiment, as shown in  FIG. 14 , there are four columns to arrange artworks and the painting tones assigned to each column are the oil painting tone, watercolor painting tone, pastel tone, and colored pencil drawing tone. 
         [0121]    Then, if free space is available in the column to which the painting tone of the artworks is assigned (step SC 360 : YES), the CPU  20  arranges the image data of the artworks in the column (step SC 361 ). In the processing in step SC 361 , if, for example, other images are present around (in the same column or adjacent columns) a location where artworks should be arranged, the CPU  20  ensures proper space between each artwork by fine-tuning positions of other images if necessary. 
         [0122]    Then, the CPU  20  returns to the processing in step SC 353  to read new artworks to be displayed. 
         [0123]    On the other hand, if free space is not available in the column to which the painting tone of the artworks is assigned (step SC 360 : NO), the CPU  20  does not arrange the image data of the artworks to be displayed this time in the display buffer  30 . In the processing in step SC 360 , if the painting tone of artworks to be displayed is different from the painting tone currently assigned to each column, the CPU  20  also determines that a free space is not available and does not arrange the image data of the artworks to be displayed this time in the display buffer  30 . 
         [0124]    Then, if the CPU  20  determines that a free space is not available, the CPU  20  subsequently determines whether a free space is available in columns to which different painting tones from the painting tone of the artworks to be displayed this time are assigned (step SC 362 ). Then, if a free space is available in a column to which a different painting tone is assigned (step SC 362 : YES), the CPU  20  returns to the processing in step  353  to read new artworks to be displayed. 
         [0125]    Subsequently, while a free space to arrange new artworks is present in any column (step SC 362 : YES), the CPU  20  repeats the processing in step SC 353  and thereafter described above. Then, when a free space to arrange new artworks is available in none of the columns (step SC 362 : NO), the CPU  20  terminates the arrangement processing. 
         [0126]    Then, a plurality of artworks arranged in the display buffer  30  by the arrangement processing is displayed at a glance on a display screen  600  of the terminal  1 - 1  as shown in  FIG. 14  in the end by the processing in step SC 302  in  FIG. 12 . Incidentally,  FIG. 14  is a diagram showing a state in which an artwork D 1  arranged in the latest position of the column of the colored pencil is an artwork of a pay member or a premium member and a display frame  14 A described above is displayed around the artwork. The display frame  14 A shown in  FIG. 14  is for the sake of convenience and actually a display frame imitating a picture pattern of the type corresponding to the membership type of the creator of the artwork D 1  is displayed. 
         [0127]    On the other hand, separately from the above processing, if the timing of the page arrangement processing is when scrolling is instructed from the user (step SC 351 : YES), the CPU  20  first determines whether the scrolling direction instructed from the user is the vertical direction (downward direction) (step SC 363 ). 
         [0128]    If the scrolling direction is the vertical direction (step SC 363 : YES), the CPU  20  moves all images (artworks) arranged in the display buffer  30  in the vertical direction (step SC 364 ). The amount of movement at this point is a preset amount of movement and is, for example, an amount that ensures space allowing one or two artworks of the minimum display size to be arranged in the top position of each column. 
         [0129]    Then, the CPU  20  proceeds to the processing in step SC 352  to perform the above processing. Accordingly, for example, the display of artwork displayed in the bottom position of the column of each painting tone is completed and instead, a new artwork is displayed in the top position. 
         [0130]    If, in contrast to the above, the scrolling direction instructed from the user is the horizontal direction (step SC 363 : NO), the CPU  20  moves all images (artworks) arranged in the display buffer  30  in the horizontal direction, that is, in the left direction or right direction (step SC 365 ). The amount of movement at this point is an amount of movement that is fixedly preset and moves artworks arranged in each column to the adjacent column. Further, the CPU  20  moves settings of the painting tone assigned to each column by one column in the same direction as the moving direction of artworks arranged in each column (step SC 366 ). 
         [0131]    Then, the CPU  20  proceeds to the processing in step SC 353  described above to perform the above processing in a state in which the assignment of the painting tone to each column is changed. Accordingly, in the example shown in  FIG. 14 , instead of a group of artworks displayed in the column of the oil painting tone or the column of the colored pencil, a group of artworks of another painting tone that has not been displayed is newly displayed. 
         [0132]    According to the present embodiment, as described above, many artworks can be displayed efficiently for the user by displaying many artworks (images) stored in the server  10  in units of pages at a glance. 
         [0133]    The display size is increased for an artwork with increasing value to make an artwork with increasing value more highlighted. An artwork with an increasing point number is made more valuable. The value of an artwork by a premium member is set higher than the value of an artwork whose creator is a simple pay member. Moreover, a point number is automatically added to an artwork in which a face is present (can be detected) to make such an artwork more valuable than an artwork without a face. 
         [0134]    A display frame is added to only artworks of pay members or premium members to make such artworks of pay members or premium members more highlighted than artworks of free members. Further, a display frame causing a sense of higher quality is added to artworks of premium members to make such artworks more highlighted than artworks of pay members. 
         [0135]    Therefore, many artworks can be made to display efficiently in such a manner that user&#39;s interests are awakened. At the same time, artworks can be displayed at a glance by handling artworks with a high point number relatively more preferential than artworks with a low point number, artworks in which a face is present more preferential than artworks without a face, and artworks by premium members more preferential than artworks by pay members. 
         [0136]    In the present embodiment, artworks by pay members or premium members are made more highlighted than artworks by free members by adding a display frame for the display at a glance, but instead of adding a display frame, for example, such artworks may be made more highlighted by showing the frame in an outer circumferential portion of artworks distinctly or blinking the frame. 
       Second Embodiment 
       [0137]    Next, the second embodiment of the present embodiment will be described.  FIG. 15  is a flow chart showing the screen display processing concerning the display of artworks when the server  10  displays many artworks at a glance on the Internet in the present embodiment. 
         [0138]    In the screen display processing, the CPU  20  performs page processing to display at a glance image data of many artworks posted to the server  10  and stored in the artwork area  202  (step SC 401 ). The processing in step SC 401  is the display processing at a glance (SC 4 ) in the process shown in  FIG. 5  and is the processing that causes the screen of the terminal  1 - 1  of the user accessing the server  10  to display many artworks represented by image data. 
         [0139]    The page display processing in step SC 401  is processing that makes a time line display that causes many artworks to display like a flow over time. In the time line display in the present embodiment, as shown in  FIGS. 17A to 17C , many artworks are arranged in 4 rows×4 columns in a page (one screen) and a group of artworks in each column is displayed by moving the group of artworks like a flow at a predetermined speed determined for each column downward from above (Y direction). 
         [0140]    That is, each image of the ABCD column, EFGH column, IJKL column, and MNOP column is moved like a flow in the Y direction at mutually different speeds. Incidentally, the display space of each artwork in the time line display is fixed to a preset space. 
         [0141]    In the present embodiment, images in each column are caused to display by flowing in the Y direction at different speeds and viewing an order of  FIG. 17A ,  FIG. 17B , and  FIG. 17C  in time sequence shows that, if these screens are screens, for example, every 10 seconds, the artwork A flows faster than the artwork E and the artwork I is fixed at least 30 seconds. The column of the artwork M moves in the same way as the column of the artwork A. Therefore, artworks that flow slowly like the column of the artwork E and the column of the artwork I greet the eyes of viewers longer than artworks A or M that flow fast. 
         [0142]    Incidentally, the page display processing is repeatedly performed in predetermined processing timing until, as described later, a page update is instructed, an artwork is selected, or the end of the display at a glance is instructed by the user. 
         [0143]      FIG. 16  is a flow chart showing content of the above page display processing. In the page display processing, the CPU  20  determines whether this processing timing is movement timing when one of columns in the page should be moved. When the processing is started, no image is displayed at a glance (step SC 501 : NO, step SC 502 : NO) and the CPU  20  reads, for example, image data to be displayed in order of date into the work memory from image data (JPEG data) of many artworks posted to the server  10  and stored in the artwork area  202  (step SC 503 ). 
         [0144]    Next, the CPU  20  converts the read image data into a bitmap format in the work memory (step SC 504 ) and then checks the value of the artwork selected as an image to be displayed (step SC 505 ). Also in this embodiment, the value of an artwork is a generic name for information that assigns weights to an artwork such as the point number, access count, download count, and membership type of the creator of each artwork which are pieces of attribute information attached to each artwork and concrete content thereof is as described in the first embodiment. 
         [0145]    Then, the CPU  20  determines the display column in accordance with the checked value (step SC 506 ). That is, the CPU  20  determines which column of the four columns shown in  FIGS. 17A to 17C  flows or displays the artwork of the image to be displayed. 
         [0146]    In the present embodiment, the speed at which each artwork flows is preset for each column. More specifically, the first column in which the artworks A, C, and D are arranged and the fourth column in which the artworks M, N, O, and P are arranged as shown in  FIG. 17A  have the same speed and the fastest speed, the speed of the second column in which the artworks E, F, G, and H are arranged is the second fastest, and the speed of the third column in which the artworks I, J, K, and L are arranged is the slowest. 
         [0147]    In step SC 506 , the CPU  20  first groups artworks to be displayed into three levels of the a high importance level, a medium importance level, and a low importance level in descending order of value described above. 
         [0148]    The CPU  20  assigns the third column whose speed of flow is the slowest to artworks contained in the high-level group as the display column and the second column whose speed of flow is the second slowest to artworks contained in the medium-level group as the display column. The first column and the fourth column whose speed of flow is the fastest are alternately assigned to artworks contained in the low-level group as the display column. 
         [0149]    Then, the CPU  20  arranges image data of artworks that are images to be displayed in bitmap format in predetermined row positions of the display column determined as described above and in which image data of other artworks is not arranged in the display buffer  30  (step SC 507 ). At this point, new image data is successively arranged from the above row position. 
         [0150]    Then, the CPU  20  repeats the above processing in steps SC 503  to SC 507  until artworks are arranged in all positions of 4 rows×4 columns in the display buffer  30 . In the meantime, though not shown, if no free space is available in the display column determined in step SC  506  for any artwork that becomes an image to be displayed, the CPU  20  discards image data of the artwork and associates the corresponding image ID and information (such as the column number) indicating the determined display column. The image ID and information are added to a display waiting list described later. 
         [0151]    When artworks are arranged in all positions of 4 rows×4 columns in the display buffer  30  (step SC 502 : YES), all image data in the display buffer  30 , that is, images for one screen are displayed in a page (step SC 518 ). 
         [0152]    Accordingly, for example, as shown in  FIG. 17A ,  16  artworks (more accurately, reduced images of artworks) ranging from the artwork A to the artwork P are displayed on the display screen  600  of the terminal  1 - 1 . Incidentally, the display order of artworks in each column is the order of date downward from above. 
         [0153]    After the above page display is made once, each time the movement timing to move images of one of columns in the page comes (step SC 501 ), the CPU  20  repeatedly performs processing in step SC 508  and thereafter. 
         [0154]    In the present embodiment, as described above, the first column (leftmost column) in which the artworks A, B, C, and D are arranged and the fourth column (rightmost column) in which the artworks M, N, O, and P are arranged as shown in  FIG. 17A  have the same speed and the fastest speed, the speed of the second column in which the artworks E, F, G, and H are arranged is the second fastest, and the speed of the third column in which the artworks I, J, K, and L are arranged is the slowest. Thus, the first column and the fourth column have the largest number of times to become the display column in which images should be moved hereinafter, called the display column to be moved) and the second column has the second largest number of times and the third column has the smallest number of times. 
         [0155]    Then, when the movement timing comes, the CPU  20  moves all image data of the corresponding display column, that is, the display column to be moved downward by a row in the display buffer  30  (step SC 508 ). Accordingly, free space is available in the top row of the display column to be moved. At this point, image data that has been in the bottom row is discarded. 
         [0156]    Next, the CPU  20  references the display waiting list described later to determine whether there is any artwork to be displayed prior to other artworks in the display column to be moved this time. Then, if there is no artwork to be displayed (step SC 509 : NO), the CPU  20  checks the value of image data of the next new artwork in order of date in artworks stored in the artwork area  202  according to the same procedure as in step SC 505  (step SC 510 ) and then determines the display column of the new image data according to the same procedure as in step SC 506  (step SC 511 ). 
         [0157]    Then, if the display column of new image data is to be moved this time, that is, free space is available in the display column of the new image data (step SC 512 : YES), the CPU  20  reads the new image data from the artwork area  202  (step SC 513 ). 
         [0158]    Next, the CPU  20  converts the read image data into bitmap data (step SC 516 ) and arranges the bitmap data in a free position in the display buffer  30 , that is, in the top row of the display column to be moved (step SC 517 ) and then makes a page display of all image data after the update in the display buffer  30 . That is, an image for a new screen that has changed to a state in which three existing artworks of the display column to be moved have moved downward by one row (step SC 518 ). 
         [0159]    On the other hand, if, in step SC 512 , the display column of new image data is not to be moved this time, that is, free space is not available in the display column of the new image data (step SC 512 : NO), the CPU  20  adds the image data to the display waiting list (step SC 514 ). The display waiting list is a list provided in an internal memory of the CPU  20  and, more specifically, table data that associates and stores the image ID and information (such as the column number) indicating the display column determined for the image (artwork) indicated by the image ID. 
         [0160]    After adding new image data to the display waiting list in step SC 514 , the CPU  20  returns to step SC 510  to check the value of image data of the next new artwork in order of date in artworks stored in the artwork area  202  again. Then, the CPU  20  repeats the above processing and then, if the display column for the new image data matches the display column to be moved this time (step SC 512 : YES), the CPU  20  displays a new page in which the image data, that is, the new artwork is arranged in the top row of the display column to be moved this time (steps SC 513  to SC 518 ). 
         [0161]    Then, if the display waiting list stores information about image data for which the display column matching the display column to be moved is associated at any movement timing (step SC 509 : YES), the CPU  20  reads the image data, that is, new image data waiting to be displayed as an image to be displayed from the artwork area  202  (step SC 515 ). At this point, information about the new image data is deleted from the display waiting list. Then, the CPU  20  displays a new page in which the new image data (artwork) is arranged in the top row of the display column to be moved this time (steps SC 516  to SC 518 ). 
         [0162]    Subsequently, each time the movement timing comes, the CPU  20  repeats the processing of steps SC 508  to SC 518  described above. Accordingly, many artworks posted to the server  10  and stored in the artwork area  202  are arranged in the column in accordance with the value of each artwork is displayed like a flow at the speed determined for each column. 
         [0163]    Then, in the screen display processing, as shown in  FIG. 15 , if the page update is instructed from the user (step SC 402 : YES) while the above page display is made, the CPU  20  initializes the display buffer  30  at this point (step SC 407 ) and then makes the page display described above (step SC 401 ). At this point, a new page is displayed by undergoing the processing in steps SC 502  to SC 507  in  FIG. 16 . That is, a page in which new  16  artworks that were not displayed immediately before are displayed at a glance is displayed immediately after the page update is instructed and then, a new time line display is started. 
         [0164]    Subsequently, if one of artworks is selected by a user in the page being displayed while the above page display is made (step SC 403 : YES), the CPU  20  reads the image data of the artwork from the artwork area  202  (step SC 404 ) and enlarges and displays the image data (step SC 405 ). The enlargement processing causes the screen of the terminal  1 - 1  of the user accessing the server  10  to display an artwork in the actual size. 
         [0165]    Then, on the server  10 , the CPU  20  returns to step SC 401  to continue to make the page display of many artworks until the user instructs the end of the display at a glance (step SC 406 : NO). Then, when the end of the display at a glance is instructed (step SC 406 : YES), the CPU  20  terminates the screen display processing. 
         [0166]    According to the present embodiment, as described above, many artworks can be displayed efficiently for the user by displaying many artworks (images) stored in the server  10  in units of pages at a glance. At the same time, when many artworks are displayed at a glance, many artworks can be made to display in such a way that user&#39;s interests are awakened by making the above time line display thereof. 
         [0167]    Moreover, in the time line display according to the present embodiment, each artwork is displayed in a moving state like a flow and the speed of the flow (movement) of each artwork is changed in accordance with the value of each artwork. Therefore, the flow of each artwork can be changed so that many artworks can be displayed so as to awaken users&#39; interests still more. 
         [0168]    Also in the time line display according to the present embodiment, the speed of the flow (movement) of an artwork with increasing value is made slower so that an artwork with increasing value is made easier to view and the display time thereof is made longer. The value of an artwork is increased with an increasing point number of the artwork and the value of an artwork by a premium member is set higher than the value of an artwork whose creator is a simple pay member. Moreover, a point number is automatically added to an artwork in which a face is present (can be detected) to make such an artwork more valuable than an artwork without a face. 
         [0169]    Therefore, artworks can be displayed at a glance by handling artworks with a high point number relatively more preferential than artworks with a low point number, artworks in which a face is present more preferential than artworks without a face, and artworks by premium members more preferential than artworks by pay members. 
         [0170]    In the present embodiment, a plurality of artworks in a page is made to display like a flow in the vertical direction (Y direction) for the time line display, but the present invention is not limited to this example and artworks may naturally be caused to display like a flow in the horizontal direction (X direction) or in a slanting direction. For the sake of convenience, the arrangement of artworks in a page is assumed to have 4 rows×4 columns in the present embodiment, but the number of artworks in each column and each row is arbitrary. 
         [0171]    Also in the present embodiment, the value of each artwork is assumed to be determined based on the point number of the artwork and the membership type of the creator of the artwork. However, the value of each artwork may be determined as follows. The value of each artwork may be determined based on, for example, one piece of attribute information of the point number, access count (browsing count), and download count, any plurality of pieces of attribute information, or the membership type of the creator of each artwork only. Alternatively, the value of each artwork may be determined based on the attribute information excluding the membership type of the creator of the artwork and the download count, or based on the membership type of the creator of the artwork and a plurality of pieces of attribute information. 
         [0172]    Also in the present embodiment, the time line display of each artwork is made basically in order of date, but the time line display of each artwork may be made randomly. The moving speed of artworks in each column may be set randomly without fixing the speed under the condition that at least the same moving speed is not set to columns of artworks having different values. 
         [0173]    Also in the present embodiment, the length of time in which artworks greet the eyes of users is controlled by changing the moving speed depending on the value of each column of artworks, but, instead of moving artworks, artworks may be displayed in the same position while changing the timing to switch to the next image, that is, the display duration. In  FIGS. 17A to 17C , for example, each artwork moves at a different speed from column to column, but the artwork A may be replaced in the same position by the next artwork AA after 15 seconds, the artwork E may be replaced in the same position by the next artwork EE after 30 seconds, and the artwork I may be replaced in the same position by the next artwork II after 1 minute. 
         [0174]    Also in the present embodiment, the CPU  20  makes the above time line display for all artworks posted to the server  10  and stored in the artwork area  202  when performing screen display processing. However, artworks to be displayed in the time line display may be limited to artworks having specific painting tones. 
         [0175]      FIG. 18  is a flow chart showing a modification of the screen display processing in that case and corresponding to  FIG. 15 . When artworks to be displayed are limited to artworks having specific painting tones, as shown in  FIGS. 17A to 17C , if the user instructs to change the painting tone while the time line display of a plurality of artworks intended for artworks of an optional painting tone is made (step SC 408 : YES), the above page display processing may be performed after the painting tone of artworks to be displayed being switched in a predetermined order (step  409 ). 
         [0176]    While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. For example, the present invention can be practiced as a computer readable recording medium in which a program for allowing the computer to function as predetermined means, allowing the computer to realize a predetermined function, or allowing the computer to conduct predetermined means.