An image processing device (1) provides a client device (3) with a first test pattern image, acquires the results of evaluation concerning distinguishability of the image by human eyes, acquires color expression characteristics of the client device (3) according to the results, provides the client device (3) with a second test pattern image, acquires the results of evaluation concerning appearance of the second test pattern to human eyes, acquires the color balance characteristics of the client device (3), subjects the image data to be provided to color correction on the basis of the characteristics, and provides the client device (3) with the image data, thereby enhancing the color reproductivity of the image data on the client device (3) side.