Abstract:
Techniques for transmitting graphical images in a network environment are described. According to the techniques, the amount of data of the graphical images that is transmited is customized in accordance with client and/or server supplied information. The techniques enable graphical images to be transmitted more efficiently than previously possible, thus saving precious network bandwidth and reducing transmision time. The invention is particularly suitable for network (Internet or Internet) implementations wherein graphical images often need transferred.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of U.S. application Ser. No. 09/036,268, filed Mar. 6, 1998 now U.S. Pat. No. 6,501,472 which is a continuation of U.S. application Ser. No. 08/622,528 filed Mar. 25, 1996, now U.S. Pat. No. 5,764,235. 

   BACKGROUND OF INVENTION 
   1. Field of the Invention 
   The present invention relates to graphical images and, more particularly, to the transmission of graphical images. 
   2. Description of the Related Art 
   To meet the multimedia revolution, computers have become more powerful and have provided more multimedia support. In particular, graphic capabilities of personal computers have been greatly enhanced in recent years due to technological improvements in peripheral devices and software products. Input peripheral devices, such as scanners and CD-ROM players, enable personal computers to obtain graphical image files. Software products can also be used to create graphical images using paint or drawing programs. Output peripheral devices, such as printers and plotters, can be used to print the graphical images. 
   The Internet (also referred to as the World Wide Web) is also part of the multimedia revolution because it acts as a large depository of image files which can be down-loaded for viewing, storing and/or printing. For example, web pages available at web sites on the Internet commonly include graphical images that are to be down-loaded to visitors to the web site. 
   One major problem, however, with down-loading graphical image files from the Internet is bandwidth constraints. Due to the large file size of graphical image files, a high bandwidth is needed for transmission of graphical image files in acceptable amounts of time. The bandwidth constraints are primarily due to how user&#39;s computers connect to the Internet. Computers are typically connected to the Internet using modems and standard telephone lines. Some users are fortunate enough to couple to the Internet with high speed connections (e.g., T1, T3 or ISDN lines). In any case, most users are connected to the Internet through 14.4 kbits/second or 28.8 kbits/second modems which are relatively slow and therefore a bandwidth constraint for down-loading sizable graphical image files. Hence, the average time it takes to down-load a graphical image file to a user&#39;s computer is unduly long. Thus, the communication links by which user&#39;s computers connect to the Internet are the transmission bottleneck. 
   Compression techniques can be used to provide some relief to the transmission bottleneck. By compressing the graphical image files using known compression techniques (such as JPEG), the graphical image file can be reduced in size. However, the reduction in size provided by compression does lead to distortion. The amount (or rate) of compression an image can withstand before showing noticeable distortion depends of the Image and the viewing medium, but a nominal amount would be 15- to 1 compression. Although a limited amount of compression is acceptable, there is a limit as to the compression rate that still produces acceptable quality. The amount of compression achieved by existing compression techniques does not provide both high quality and rapid transmission over modem connections. The author of an image who prepares a graphical image file for the image that is to be accessed through a network must choose a level of compression to achieve a tradeoff between image quality and transmission time. Consequently, compression helps with the bandwidth constraints or transmission bottleneck, but does not sufficiently solve the problem. 
   The transmission of graphical image files in networks within companies (internet) face similar problems. While some users may have high speed connections to servers on the internet, other users have much slower modem connections. However, both types of users need to obtain graphical image files with acceptable response times. Hence, in the internet case, the communication links by which user&#39;s computers connect to the internet are also the transmission bottleneck. 
   Thus, there is a need for improved techniques for transmission of graphical image files in a network environment so that the available bandwidth is used more efficiently. 
   SUMMARY OF INVENTION 
   Broadly speaking, the invention relates to techniques for transmitting graphical images in a network environment wherein the amount of data of the graphical images that is transmitted for each of the graphical images is customized in accordance with client and/or server supplied information. The techniques thus enable graphical images to be transmitted more flexibility and efficiently. As a result, the amount of data transmitted is customized for the particular situation. Hence, excess data need not be transmitted when the requester does not need or desire it. Alternatively, a request for a very high quality image can be satisfied. Accordingly, the invention makes significantly better and more intelligent use of the available bandwidth of the network environment. The invention can be implemented in numerous ways, including as a method, process, system, and a computer readable media. 
   As a computer-implemented method for transmitting a graphical image from a server machine to a client machine, an embodiment of the invention performs the operations of: receiving, at the server machine, a request for a graphical image from a client machine, the graphical image being stored on the server machine and having a predetermined total image size; obtaining image control information; determining an appropriate amount of data for the graphical image to be transmitted based on at least the image control information, the appropriate amount being less than or equal to the predetermined total image size; and transmitting the graphical image to the extent of the appropriate amount from the server machine to the client machine. 
   As a computer-implemented method for transmitting a graphical image from a server machine to a client machine, another embodiment of the invention performs the operations of receiving, at the server machine, a request for a graphical image from a client machine; negotiating between the server machine and the client machine to determine a quality-size tradeoff for the graphical image; and transmitting the graphical image to the extent of the quality-size tradeoff from the server machine to the client machine. 
   As a computer-implemented identification process for a server machine connected to a client machine over a network, an embodiment of the invention performs the operations of, receiving, at a server machine, a capabilities query from a client machine; sending a response to the capabilities query from the server machine to the client machine; determining whether the client machine supports image customization based on the capabilities query; and identifying the client machine as a client machine that supports image customization when the determining operation determines that the client machine supports image customization. Preferably, the image customization operates to set a reduced total image size for a graphical image. 
   As a computer-implemented method for receiving at a client machine a graphical image from a server machine, an embodiment of the invention includes the operations of sending a request for a graphical image to a server machine; sending image control information from the client machine to the server machine; and receiving from the server machine the graphical image of a determined amount, the determined amount being based on at least the image control information. Preferably, the determined amount is a reduced amount, and the graphical image file received also has a determined format based on at least the image control information. As examples, the determined format may be suitable for storing, displaying or printing an image associated with the graphical image file received. 
   As a system for transmitting graphical image files, an embodiment of the invention includes a client machine operating to store client image control information, request a graphical image file, and forward the client image control information; a server machine operating to store graphical image files, receive the request and the client image control information from the client machine, determine an appropriate amount of data for the graphical image file requested, and forward the graphical image file requested with the appropriate amount of data: and a network for coupling together the client machine and the server machine, wherein the request being forwarded, the client image control information, and the graphical image file being forwarded each traverse the network. Preferably, the graphical images stored in the server machine are stored using a progressive compression format. The network can be any network suitable for interconnecting computers. 
   As a computer readable media containing program instructions for transmitting a graphical image from a server machine to a client machine, an embodiment of the invention includes: first computer readable code devices for receiving, at the server machine, a request for a graphical image from a client machine; second computer readable code devices for negotiating between the server machine and the client machine to determine a quality-size tradeoff for the graphical image requested; and third computer readable code devices for transfer. Letting the graphical image file to the extent of the quality-size tradeoff from the server machine to the client machine. 
   The advantages of the invention are numerous. One advantage of the invention is that graphical images can be transmitted over a network with a reduced amount so as to conserve precious network bandwidth, improve transmission time, and to reduce loads placed on server machines. Another advantage is that a user has a choice as to the amount of a graphical image file needed depending on an intended use for the image. For the images are simply being displayed in a small one inch by one inch arrangement, then only a small amount of the graphical image file need be transmitted. On the other hand, if the image is to be printed with high quality at a page-size, then a substantially larger amount of the graphical image file needs be transmitted (but this is typically still less than the complete graphical image file). In either case, less data is transmitted so less bandwidth is required and transmission time is improved. Further, in the case where the image is to be printed with picture quality on a large format, then a large amount (perhaps all) of data would be transmitted, which is very likely more data than would be conventionally available. The format of the data can also vary with the intended use (e.g., display format, printer formats, storage formats, etc.). Another advantage of the invention is that an author of an image need only store the associated graphical image file once in a high quality format, thereafter, the invention operates via a negotiation process between client and server, to meter down the amount of the graphical image file as is warranted. Yet another advantage of the invention is that moves with technology in that as transmission bandwidth becomes greater or transmission rates become faster, the previously stored image files are automatically useable without changes. 
   Other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
       FIG. 1A  is a basic block diagram of a communications system according to an embodiment of the invention; 
       FIG. 1B  is a detailed block diagram of the communications system illustrated in  FIG. 1 ; 
       FIG. 2  is a basic block diagram of an Internet arrangement; 
       FIG. 3  is a detailed block diagram of an Internet arrangement; 
       FIG. 4A  is a flow diagram of handshake processing at a client machine according to an embodiment of the invention; 
       FIG. 4B  is a flow diagram of handshake processing at a server machine according to an embodiment of the invention; 
       FIG. 5  is a flow diagram of image processing performed by a server machine processing according to an embodiment of the invention; 
       FIG. 6A  is a representative diagram of a modified image file according to an embodiment of the invention; 
       FIGS. 6B and 6C  are bar charts illustrating amount of data as a percentage of the total amount of available data; 
       FIG. 7  is a flow diagram of client processing according to an embodiment of the invention; 
       FIG. 8  is a flow diagram of server processing according to an embodiment of the invention; 
       FIG. 9  is a flow diagram of web browser processing according to an embodiment of the invention; 
       FIG. 10  is a flow diagram of web server processing according to an embodiment of the invention; 
       FIG. 11  is a flow diagram illustrating image customization processing according to an embodiment of the invention; and 
       FIG. 12  is a flow diagram of author image processing. 
   

   DETAILED DESCRIPTION 
   Embodiments of the invention are discussed below with reference to the drawings. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes as the invention extends beyond these limited embodiments. 
     FIG. 1A  is a basic block diagram of a communications system  100  according to an embodiment of the invention. The communications system  100  includes a server  102  and a client  104 . Images are stored on the server  102  and each image typically has a predetermined physical size and resolution that lead to a total image size. Each such image is stored on the server  102  as an image file. The client  104  sends a request for an image over a link  106  to the server  102 . The server  102  then in turn sends an appropriate amount of data for the corresponding image file to the client  104  over a link  108 . 
     FIG. 1B  is a detailed block diagram of the communications system  100  illustrated in FIG.  1 . The server  102 , besides conventional processes and data, includes a server handshake process  112 , an image customization process  114 , and server image control data  116 . The client  104 , besides conventional processes and data, includes a client handshake process  118  and client image control data  120 . The server handshake process  112  cooperates with the client handshake process  118  to allow the client  104  and the server  102  to determine whether they both support image customization. If both the client  104  and the server  102  do support image customization, then the server  102  is able to use the image customization process  114  on image files to be transmitted to the client  104 . The image customization process  114  operates to customize both the amount of data and the format of graphical image files to be sent to the client  104 . In performing the image customization process  114 , the server  102  makes use of the server image control data  116  and/or the client image control data  120  so that the customization is intelligently performed. The client image control data  120  is data or information obtained from the client  104  that is useful in determining both the suitable amount of data and/or format for the graphical image files to sent. The server image control data  116  is data or information obtained from the server  102  that is useful in determining both the amount of data and/or format for the graphic image files to be sent. 
     FIG. 2  is a basic block diagram of an Internet arrangement  200 . The Internet arrangement  200  includes a web server  202 , a web browser  204  and the Internet  206 . The web server  202  is more generally referred to as a server or a server machine and the web browser  204  is more generally referred to as a client or a client machine. The Internet  106  is an international network of interconnected computers as is well known in the art. The web server  202  couples to the Internet  206  via a link  208 . The web browser  204  couples to the Internet  206  via the link  210 . The web browser  204  sends a web page request over a link  210  to the web server  202 . The web server  202  then in turn sends the corresponding web page HTML file to the web browser  204  over a link  210 . Then, the web browser  204  searches through the web page HTML page to determine whether or not graphical image files are contained within the web page. If image files are contained within the web page, the web browser  204  requests the image files from the web server  202  over the link  208 . The web server  202 , upon receiving the request for the image file, forwards the appropriate image file to the web browser  204  through the Internet  206  and the links  208  and  210 . 
   The Internet arrangement  200  is one of many possible implementations of the communications system  100 . In should be recognized that the invention is applicable to any network environment whether it be the Internet or various intranets such as Local-Area Networks (LANs) or Wide-Area Networks (WAN). The network can be a wired network, a wireless network, or some combination of both. 
   The transmission of large amounts of image data from the server  102  (web server  202 ) to the client  104  (web browser  204 ) requires a large amount of bandwidth in the communications path. In  FIGS. 1A and 1B  the communications path is simply the link  108  and in  FIG. 2  the communications path is the Internet  206  and the links  208 ,  210 , but these illustrative communication paths are two representative communication paths through a network of computers. The need for large amounts of bandwidth is conventionally needed to transfer image files (i.e., graphics data) over a network from a server machine to a client machine. As an example, a simple drawing or graphic can be 20 NM of data and a medium complexity drawing from a drawing program can be upwards of 100 NM of data. Thus, transmission of image files is data intensive. As a result, if a large bandwidth is not available, then transmission speed must be very fast, else the server cannot transmit (e.g., download) the image data with satisfactory. speed. Other problems which result are that the server is unable to service as many clients and even those that it does service must endure considerable delays. 
   The invention provides a solution to these and other problems by customizing the amount of image data to be transmitted in accordance with client and/or server supplied information. The invention thus enables graphical image files to be transmitted more flexibility and efficiently. As a result, the amount of data transmitted is customized for the particular situation. Hence, excess data need not be transmitted when the requester does not need or desire it. Alternatively, a request for a very high quality image can be satisfied. Accordingly, the invention makes significantly better and more intelligent use of the available bandwidth of a network. 
     FIG. 3  is a detailed block diagram of an Internet arrangement  300 . The Internet arrangement  300  includes a client machine  302  and a server machine  304 . The server machine  304  is typically directly connected to the Internet  106  over a high speed link. The client machine  302  is typically a computer system which connects to the Internet  106  through a telephone network  306  and an Internet service provider  308 . ( 00411  The improved techniques for transmitting graphical images according to the invention can be implemented by numerous computer systems. The client machine  302  illustrated in  FIG. 3  represents an exemplary computer system. 
   The client machine  302  includes a microprocessor  310  which is coupled to a random access memory (RAM)  312 , a read only memory (ROM)  314  and an I/O controller  316 . The I/O controller  316  is coupled to a bus  318 . Also coupled to the bus  318  is a disk controller  320 , a video controller  322  and a network port  324 . A disk storage device  326  is coupled to the disk controller  320 . A display device  330  is coupled to the video controller  322 . The network port  324  in the exemplary embodiment includes a modem which couples to the telephone network  306  via telephone subscriber lines. The client machine  302  is usually also coupled to a printer (not shown) through a printer port. 
   The client machine  302  together with an operating system (not shown) operate to execute computer code. The computer code may reside on the RAM  312 , the ROM  314 , or the disk storage device  326 . The computer code could also reside on a removable program medium  328  and then loaded or installed onto the client machine  302  when needed. Removable program mediums include, for example, CD-ROM, PC-CARD, floppy disk and magnetic tape. 
   The client machine  302  and the sever machine  304  illustrate in  FIG. 3  also include the feature of the invention illustrated in FIG.  3 . For example, preferably computer code for the client for the client handshake process  118  is stored in the RAM  312 , the ROM  314 , the disk storage device  326  or the removable program medium  328  and performed by the microprocessor  310 . The client image control data  120  is preferably managed by the microprocessor  310  and stored in the RAM  312 , the disk storage device  326  or the removable program medium  328 . Similarly, the server handshake press  112 , the image customization process  114  and the server image control data  116  associated with the sever machine  04  are effectuated by computer code within the server machine  304 . 
     FIG. 4A  is a flow diagram of client handshake processing  400  according to an embodiment of the invention. Preferably, the client handshake process  118  within the client machine ( 104 ,  204 ,  302 ) performs the client handshake processing  400 . 
   The client handshake processing  400  initially sends  402  a capabilities query to the server machine ( 102 ,  202   304 ). That is, the client machine (e.g., the web browser operating thereon) sends the capabilities query to the server machine (e.g., the web server operating thereon) via a network (e.g., the Internet  106 ). The capabilities query is constructed so as to query the server machine to determine whether it supports image customization. For example, the capabilities query may ask the server machine what image formats, compression schemes, etc. it supports. Next, a decision  404  determines whether a response (e.g., a response message) has been received from the server machine. If no response has been received, the decision block  404  causes the client handshake processing  400  to await such a response. While the handshake processing  400  is awaiting a response, a decision  406  determines whether a time-out has occurred. A time-out is determined to have occurred when a response has not been received from the server machine for a predetermined period of time. If the time-out occurs, then it is determined by default that the server machine does not support image customization, thus a customization flag at the client machine is reset  408  and then the client handshake processing  400  is complete and ends. The resetting  408  of the customization flag is used to signal the client machine that image customization is unavailable. 
   On the other hand, if a response is received from the server machine, the client handshake processing  400  continues. In particular, following block  404  when a response is received, a decision  410  determines whether the server machine supports image customization. Here, the client handshake processing  400  examines the response from the server machine to determine whether the server machine supports customization if images. 
   If it is determined that the server machine does support image customization, then the customization flag at the client machine  302  is set  412 . If, on the other hand, the server machine does not support customization of images, the customization flag at the client machine is reset  408  to indicate that customization is unavailable. The customization flag thus serves to notify the client machine as to whether image customization is available for subsequent transmission of graphical image files between the server machine and the client machine. Following block  412  or block  408 , the client handshake processing  400  is complete and ends. 
     FIG. 4B  is a flow diagram of server handshake processing  414  according to an embodiment of the invention. Preferably, the server handshake process  112  within the server machine ( 102 ,  202 ,  304 ) performs the server handshake processing  414 . 
   The server handshake processing  414  begins with a decision  416  which determines whether a capabilities query has been received from a client machine. The decision  416  causes the server handshake processing  414  to await the reception of a capabilities query. Once a capabilities query is received, a response (e.g., a response message) is sent  418  to the client machine. Then, a decision  420  determines whether both the client and server machines support image customization. The server machine knows whether it supports image customization, and the server machine can determine whether the client machine supports image customization from the capabilities query which was received from the client machine. Next, when it is determined that both the client and server machines support image customization, a customization flag at the server machine is set  422 . Otherwise, when it is determined that one or both the client and server machines do not support image customization, a customization flag at the server machine is reset  424 . The customization flag servers to notify the server machine as to whether image customization is available for subsequent transmission of graphical image files between the server machine and the client machine. Following block  422  or block  424 , the server handshake processing  414  is complete and ends. 
   Through the client handshake processing  400  and the server handshake processing  414 , the client machine ( 104 ,  204 ,  302 ) and the server machine ( 102 ,  202 ,  304 ) are able to interact with each other to determine whether they both support image customization. Of each different client-server pair, the handshake processing  400 ,  414  is repeated. An alternative implementation could have the server machine initiate the handshake between client and server. 
     FIG. 5  is a flow diagram of image processing  500  performed by the server machine according to an embodiment of the invention. The image processing  500  is utilized by the server machine to customize the images. Namely, the data associated with a graphical image file is customized in a manner such that image quality versus size can be controlled. Specifically, the image processing  500  receives  502  a graphical image file. Typically, the graphical image file that is received  502  is stored on the server machine  304 . In the Internet context, these graphical image files typically form graphical images within web pages. Following block  502 , the graphical image file is modified  504  to have a variable or selectable quality versus size tradeoff. The modifications  504  to the graphical image file are preferably done in advance and then stored on the server machine  304  in a manner suitable for accessing the graphical image file using the variable or selectable quality versus size tradeoff. 
     FIG. 6A  is a representative diagram of a modified image file  600  according to the invention. The modified image file  600  is segmented into a first segment C,  602 , a second segment C 2   604 , a third segment C 3   606 , a fourth segment C 4   608 , and a fifth segment C.  610 . The section  602 - 610  are preferably encoded using a compression technique such as fractal compression or progressive JPEG. Each of these segments  602 - 610  contain data associated with the image represented by the graphical image file. However, each of the segments is additive to provide greater image quality but at a cost of larger image file size. The encoding of the segments is such that the first segment C,  602  can itself be displayed without any of the other segments. Then, for the next gradation in image quality or file size, the graphical image file transmitted would include the first segment C,  602  and the second segment C 2   604 . The third segment C 3   606 , the fourth segment C 4   608  and the fifth segment C,  610  are likewise additive for even greater image quality or file size. For example, in Table 1, the first segment C,  602  may be 20 KB, and the first segment C,  602  and the second segment C 2   604  may total to 100 KB. Hence, the first segment C.  602  can be used for displaying the image as a high quality, thumbnail size image or a low quality, feature size image. The combination of the first segment C,  602  and the second segment C 2   604  can be used for displaying the image as a high quality, feature size image or a low quality, full screen size image. 
   The representative diagram of the modified image file  600  illustrated in  FIG. 6A  is particularly suited for fractal compression or progressive JPEG. However, more generally, the image file can be modified  504  according to the invention using any available compression technique or other file size reduction technique. The invention is flexible enough to be able to use the most appropriate compression or other file size reduction technique for each image, quality and size. The invention can also use different techniques for different parts of an image. 
     FIGS. 6B and 6C  are bar charts illustrating amount of data as a percentage of the total amount of available data (e.g., image files size).  FIG. 6B  illustrates an example of the image customization with respect to different client transmission (modem) speeds.  FIG. 6C  illustrates an example of the image customization with res for the requested image. Notice in either of these customization, depends on the transmission modified Image file  600  can be used to provide the amounts incremental fashion. 
     FIGS. 7 and 8  are flow diagrams of the client-server interaction carried out to request and then transmit a graphical image file over a network interconnecting the client and server. The network may be of any type as previously mentioned. 
     FIG. 7  is a flow diagram of client processing  700  according to an embodiment of the invention. The client processing  700  is preferably performed by the client (client machine)  104 . 
   The client processing  700  initially requests  702  a graphical image file from the server (server machine)  102 . As an example, the request would identify the graphical image file desired together with a total image size and a requested quality level. Then, a decision  704  determines whether the customization flag is set at the client  104 . If the decision block  704  determines that the customization flag is set, then image control data is sent  706  from the client to the server  102 . On the other hand, if the decision block  704  determines that the customization flag is not set, then block  706  is bypassed. Following blocks  704  or  706 , a decision  708  determines whether the requested image data has been received from the server  102 . If not, the decision block  708  causes the client processing  700  to await reception of the requested image data (or a time-out occurs to end the processing  700 ). After the requested image data has been received, the client processing is complete and ends. 
     FIG. 8  is a flow diagram of server processing  800  according to an embodiment of the invention. The server processing  800  is preferably performed by the server (server machine)  102 . 
   The server processing  800  begins with a decision  802  that determines whether a graphical image request has been received from a client. When the decision block  802  not intended uses the data, i.e., the segments of the that in an determines that a graphical image request has not been received, the server processing  800  repeats the decision block  802  until the graphical Image request is received. Once the graphical image request is received, the server processing  800  determines  804  whether the customization flag is set at the server. Recall that the server handshake processing  414  sets or resets the customization flag at the server (FIG.  4 B). If the customization flag is set, an amount of data and/or image format for the requested image is determined  806 . Here, the image that is to be transmitted from the server to the client is customized in accordance with the invention so that the amount of data and/or format are determined in accordance with image control data from the client as well as image control data from the server. Following block  806  or following the decision block  804  when the customization flag is not set, the image data is sent  808  to the client. Thus, when both client and server support customization of the amount and/or format of the image data, then customization is performed prior to transmission; 
   otherwise, when customization is not supported the image data is sent as is without customization. 
     FIGS. 9-11  are flow diagrams of the client-server interaction carried out to request and then transmit a graphical image file over the Internet. In this situation, the network is the Internet, and the client and server are more particularly web browser and web server, respectively. 
     FIG. 9  is a flow diagram of web browser processing  900  according to an embodiment of the invention. The web browser processing  900  is preferably performed by a web browser (i.e., the web browser  204 ) because web browsers are commonly used to access and navigate through the Internet  206 . More generally, however, the web browser is a client machine such as the client machine  104 ,  302 . 
   The web browser processing  900  initially requests  902  a web page. The request for a web page is sent by the web browser  204  through the Internet  206  to the web server  202 . The web browser processing  900  then determines  904  whether the web page HTML file has been received in response to the request for the web page. Until the web page HTML file is received (or a time-out occurs to end the processing  900 ), the web browser processing  900  awaits its reception. Once the web page HTML file has been received, a decision  906  determines whether the web page HTML file includes a graphical image file. If the web page HTML file does include a graphical image file, a request for the graphical image fileis sent  908  to the web server  102 . Then, a decision  910  awaits reception of the determined image data from the web server  102  (or a time-out occurs to end the processing  900 ). Following block  910  when the determined imaged data has been received or following block  906  when the web page HTML file does not include a graphical image file, the web page is displayed  912 . In the case in which blocks  908  and  910  are performed, the web page displayed  912  includes a graphical image file. In the case in which the decision block  906  determines that the web page HTML file does not include a graphical image file, blocks  908  and  910  are skipped and the web browser processing  900  causes the web page to be displayed  912  without any graphical image file. 
     FIG. 10  is a flow diagram of web server processing  1000  according to an embodiment of the invention. The web server processing  1000  is preferably performed by a web server (i.e., the web server  202 ) because web servers are commonly used access sites (e.g., web sites) on the Internet  206 . More generally, however, the web server is a server machine such as the server machine  102 ,  304 . 
   The web server processing  1000  begins with a decision  1002  that determines whether a web page request has been received. If a web page request has been received from a web browser (e.g., web browser  204 ), the web page HTML file requested is sent  1004  to the web browser that has requested the web page. Next, following block  1004  or following the decision block  1002  when a web page is not being requested, a decision block  1006  determines whether a graphical image file request has been received. When a graphical image file request has been received from a web browser, the web server processing  1000  determines  1008  an image format and file size for the requested graphical image file. In effect, the determining  1008  customizes the graphical image file based on criteria such as user&#39;s conditions, server&#39;s conditions, user&#39;s request or author&#39;s preference, The customization of the graphical image file is described in greater detail below with reference to FIG.  11 . Thereafter, the determined image data is sent  1010  to the web browser that requested the graphical image file. 
   Following block  1010  in the case in which a graphical image file request was received and processed, or following the decision block  1006  in the case when there has been no graphical image file request, a decision  1012  determines whether the web server processing  1000  has been shut down or quit. If the decision block  1012  determines that the web server processing  1000  is to be shut down or quit, the web server processing  1000  is complete and ends. On the other hand, when the web server processing  1000  has not been shut down or quit, the web server processing  1000  returns to repeat decision block  1002  and subsequent blocks, thereby forming a loop within the web server processing  1000 . 
     FIG. 11  is a flow diagram illustrating image customization processing  1100  according to an embodiment of the invention. The image customization processing  1100  is a detailed diagram of the block  1008  in FIG.  10 . 
   The image customization processing  1100  initially obtains  1102  image control data from the web browser (client image control data). The image customization processing  1100  also obtains image control data from the web server (server image control data). Next, a decision  1106  determines whether the image control data from the web browser includes a user request. If the image control data from the web browser does include a user request, a decision  1107  determines whether the user request is for an author&#39;s preference. If not, the file size for the determined image file is set  1108  to user-size, which indicate that the file size is set by a user&#39;s choice- or expected choice. On the other hand, if the decision block  1107  determines that the user request is for the author&#39;s preference, then the file size is set  1110  to the author-size, which is the file size recommended by the author of the image. 
   In the case in which the decision block  1106  determines that there is no user request within the image control data from the web browser, the file size is set  1112  to default-size, which is the default size for the image file. Following blocks  1108 ,  1110  and  1112 , a decision  1114  determines whether the file size that has been selected is greater than a maximum file size (server-Size) that the web server is willing to transmit. The server-size is primarily Influenced by control information from the web server itself, but can also be influenced by the image control information from the web browser. In any case, if the file size is greater that the server size, then the file size is set  1116  to server-size. Thus, blocks  1114  and  1116  combine to limit the file size to the server-size, which is the maximum file size that the web server is willing to support. As an example, if the web server is experiencing a heavy load, the web server can reduce the amount of data it needs to transmit to requesting web browsers by lowering the server-size. 
   Next, following block  1116  or following the decision block  1114  when the file size is not greater than the server-Size, the image format for the graphical image is determined  1118 . The image format can be determined  1118  based on various criteria, including: (i) compression techniques available at both the web browser and the web server, (ii) printer formats (e.g., raster, Postscript, bit map, etc.), (iii) display formats, (iv) size of image, and/or (v) a vector (outline) representation of the image. These criteria as well as user preferences are passed to the web server during the handshake processing  400 ,  414 . Hence, the image customization processing  1100  is intelligent enough to select a compression technique that is supportable on both image browser and the web server. In fact, there might be a particular preference for a compression technique set by a user or author or server which could be preferably selected or given some priority. Also, depending on whether the graphical image is to be displayed or printer by the user, the image customization processing  1100  selects the appropriate format. The determining  1118  of the image format can also compare various compression techniques and then selecting the one which yields the smallest amount of data yet still has the necessary image quality. When the user intends to use the graphical image file for display on a display device, the format includes a display format suitable for the display device associated with the web browser (e.g., client machine  302 ), such as RGB, raster, vector and the like. Alternatively, when the user intends to use the graphic image of printing on a printer, such as a laser printer, the format includes a printer format suitable for the printer associated with the web browser (e.g., client machine  302 ), such as dithered, CMYK, or RTL for plotting. 
   In any event image data is retrieved  1120  in accordance with the determined image format and the determined file size. Following block  1120  the image customization processing  1100  is completed and processing then returns to block  1010  of the web server processing  1000 . 
   If it later turns out that the amount of data (determined image format and/or file size) are not sufficient for a better quality image, physical size or resolution that is then requested, addition data can be transmitted so that the image can be displayed or printed at the greater quality, resolution and/or physical size. The data transmitted can be the entire amount of needed data or just the incremental amount of data. 
   The client image control data can, for example, include two basic types of data: user data and client system data. The user data includes, for example, user preference, intended use, and a specific quality level request. The intended use, for example, is for display or for printing a particular size graphical image. The user preference could be a user selected choice of quality versus size for image files or something that is predicted for the user. The client system data, for L)@ample, includes compression schemes supported by the client and server, transmission performance data, equipment information. The transmission performance data may include nominal transmission speeds (e.g., modem speeds) and measured transmission speeds. The equipment data may include a display format (e.g., display resolution) or a printer format (300 dpi) of equipment associated with the client machine. The server image control author data and server system data. The author data includes, for example, the author&#39;s preference for the image within the image file. Since the author created the image, the author may want to have some input into the quality levels for which the image can be displayed or otherwise used by users. The input from the author can be performed as detailed in  FIG. 12  below. The server system data can, for example, identify the compression scheme supported by the server machine and transmission performance of the server including nominal transmission speed and measured transmission speed. 
     FIG. 12  is a flow diagram of author image processing  1200 . The author image processing  1200  is preferably performed on a computer system. The computer system need not be the client or the server machine. The author image processing  1200  initially identifies  1202  a high quality graphical image file to process. The author is preferably the creator of the image stored within the graphical image file but could be any other individual. Next, the author selects  1204  various quality levels that are to be supported. The quality levels could, for example, follow from those indicated in Table 1 or alternatively could be based on different levels of use. The different levels of use could, for example, correspond to client side equipment, namely modem speed (14.4, 28.8, ISDN) or output device resolution. Following block  1204 , the high quality graphical image file is processed  1206  into the selected quality levels so that the image data associated with each of the selected quality levels is identified. Next, the author is given the opportunity to review and adjust  1208  the quality of the images produced at each of the levels. For example, the various images of the selected quality levels could be displayed on a display device to the author who would then increase or decrease quality levels as deemed appropriate given the nature of the particular image. The author could also view the image at different sizes. Thereafter, the author can set  1210  an author&#39;s preference level which may become part the server image control data as an indicator of the quality level and/or size the author prefers those requesting the image to obtain. 
   Much of the discussion of the invention provided above assumed that the client initiates the operations with the server. For example, in the client handshake processing  400  illustrated in  FIG. 4A , the client begins the handshake processing with the server. Many alternative configurations are possible. A first alternative is that the server could initiate the handshake processing  400 ,  414  with a client (e.g., whenever it beings communicating with a client). The server would in this situation send it server control information to the client. The client would then determine the appropriate amount and/or format for the image data to be transmitted. Then the client would send a request for the image data to the server with an indicator of the amount of data and/or format to be transmitted. The server upon receiving the request then transmits the appropriate amount of image data in the appropriate format. A second alternative is that the handshake processing  400 ,  414  could also be merged with some or all of the client and server processing  700 ,  800 . For example, the client handshake processing  400  could also send the client image control information during the handshake processing  400  and/or the server handshake processing  414  could also predetermine size versus quality tradeoffs available. Hence, it should be clear from the foregoing that the handshake and customization operations of the invention can be performed in a wide variety of different ways, with different organizations, and with different sequences. 
   The invention can also be embodied as computer readable code on a computer readable media. The computer readable media is any data storage device that can store data which can be thereafter be read by a computer system. Examples of the computer readably media include read-only memory, random-access memory, CD-ROMs, magnetic tape, optical data storage devices. The computer readable media can also be distributed over a network coupled computer systems so that the computer readable code is stored in a distributed fashion. 
   The many features and advantages of the present invention are apparent from the written description, and thus, it is intended by the appended claims to cover all such features and advantages of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation as illustrated and described. Hence, all suitable modifications and equivalents may be resorted to as falling within the scope of the invention.