A CPU extracts still images from image files recorded at predetermined time intervals among still images and moving images arbitrarily recorded in a predetermined period such as one day, and generates a time-lapse moving image by taking these extracted images as frames. That is, in addition to still images, even when a moving image file is recorded at timing corresponding to a predetermined time interval, a frame at the timing corresponding to the predetermined time interval in the moving image file is extracted, and adopted as a frame of a time-lapse moving image to be generated.