A device for making a quick change to a playback mode after photographing a subject, the device comprising: a photographing unit that obtains at least one image signal of the subject; an image processing unit that performs image processing on the at least one image signal; a buffer that stores the at least one image signal while image processing is performed by the image processing unit; and a storage unit that stores at least one compressed image signal of the at least one image signal when image processing is completed by the image processing unit, wherein the buffer comprises a database that stores index information to be assigned to the at least one image signal obtained by the photographing unit, file name and storage path information to be provided to the at least one image signal when the at least one image signal is stored in the storage unit, and characterised in that the device further comprises a digital signal processing unit that: compresses the at least one processed image signal stored in the buffer, displays the most recently stored image signal of the at least one image signal stored in the buffer on a screen, when a display input instruction to display a currently captured image during photographing is received, searches the storage unit when an input instruction to display images captured prior to the currently captured image is additionally received, if a corresponding image file is found in the storage unit, loads the found image file to display on the screen, and if the corresponding image file is not found in the storage unit, loads an image signal stored in the buffer, to display on the screen, corresponding to the index information stored in the database. a photographing unit that obtains at least one image signal of the subject; an image processing unit that performs image processing on the at least one image signal; a buffer that stores the at least one image signal while image processing is performed by the image processing unit; and a storage unit that stores at least one compressed image signal of the at least one image signal when image processing is completed by the image processing unit, wherein the buffer comprises a database that stores index information to be assigned to the at least one image signal obtained by the photographing unit, file name and storage path information to be provided to the at least one image signal when the at least one image signal is stored in the storage unit, and characterised in that the device further comprises a digital signal processing unit that: compresses the at least one processed image signal stored in the buffer, displays the most recently stored image signal of the at least one image signal stored in the buffer on a screen, when a display input instruction to display a currently captured image during photographing is received, searches the storage unit when an input instruction to display images captured prior to the currently captured image is additionally received, if a corresponding image file is found in the storage unit, loads the found image file to display on the screen, and if the corresponding image file is not found in the storage unit, loads an image signal stored in the buffer, to display on the screen, corresponding to the index information stored in the database. compresses the at least one processed image signal stored in the buffer, displays the most recently stored image signal of the at least one image signal stored in the buffer on a screen, when a display input instruction to display a currently captured image during photographing is received, searches the storage unit when an input instruction to display images captured prior to the currently captured image is additionally received, if a corresponding image file is found in the storage unit, loads the found image file to display on the screen, and if the corresponding image file is not found in the storage unit, loads an image signal stored in the buffer, to display on the screen, corresponding to the index information stored in the database.