on (small region Ry3), as shown in FIG. 20A. From this, it can be easily determined whether the image is an image in which the color balance of intermediate tones is destroyed, by determining the maximum difference ??Hs1 between the maximum values ???Str2???, ???Stg2??? and ???Stb2??? of each color of the first small region (small region Ry2), and the maximum difference ??Hs2 between the maximum v