To synchronize two image files photographed by one time of photography processing.

A control device reads from an HDD a RAW image file and a JPEG image file generated by one time of photography processing and displays a thumbnail image listing on a display screen. The control device then accepts editing of images due to a user, namely, a change of image processing parameter. If the user edits the RAW image or the JPEG image, the control device updates the image file by applying the changed image processing parameter and updates the other image file generated by one time of photography processing so as to obtain a similar effect to a case where the changed image processing parameter is applied to the image file.