An image generating apparatus includes: a diagnosis image generating section that generates, as a diagnosis image for every first time interval, at least one of a moving image in which a predetermined part of a human body or an animal is photographed and temporally continuous images based on the moving image; an image target setting section that acquires, for the diagnosis image, a first image at a predetermined time and a second image for every second time interval longer than the first time interval from the predetermined time; a pixel color converting portion that converts, of pixels of the first image and the second image, colors of pixels satisfying a predetermined condition to be distinguishable; and a display image generating section that generates an image for display using the first image and the second image whose colors of the pixels have been converted by the pixel color converting portion.