Provided is photo retouching software which is easy for photo studio personnel to use. Upon opening photo image(s), special photo retoucher converts photo image data thereof to working color space image data. At such time(s), if working ICC profile(s) is/are set which is/are different from ICC profile(s) previously embedded in such photo image file(s), color perceptual matching is carried out on the photo image data thereof based on such embedded ICC profile(s) and working ICC profile(s) when such photo image file(s) is/are opened. Furthermore, when such photo image(s) is/are displayed at monitor(s), such image data is converted to monitor color space image data through color matching using working ICC profile(s) and monitor ICC profile(s).