1. An image processing method for generating image data representing a display image on the basis of input image data, comprising: the input step of inputting a display condition for the display image and information associated with illumination light; the setting step of automatically setting a background color on the basis of the display condition for the display image and the information associated with illumination light input in the input step; and the display step of displaying the background color set in the setting step as a background of the display image.