To provide an environment-compliant image display system, image processing method, and information storage medium that enable correction of images within a shorter time, a Y value of color signals (Y3, x3, y3) measured by a color light sensor 60 and converted by an Y3x3y3 conversion section 143 is replaced with Y1, which is a Y value of an ideal environment, by a Y replacing section 142; color difference between the replaced color signals (Y1, x3, y3) and ideal color signals (Y1, x1, y1) is obtained by a color difference calculation section 145; and image display information is corrected by using that color difference (.DELTA.x, .DELTA.y).