A catalog of images whose lightness has been changed in accordance with human vision is generated. For this purpose, a first image having reference shadow lightness, a second image having reference highlight lightness, a third image having desired lightness, a fourth image having lightness that is visually perceived to evenly divide the lightness between the first image and the third image, and a fifth image having lightness that is visually perceived to evenly divide the lightness between the third image and the second image are generated. The first to fifth images are included in a catalog image.