1. An image processing device, comprising: a saturation-enhancement-amount determining device that determines a saturation enhancement amount by extracting saturation information from input image data; a color component extracting device that extracts from the input image data a plurality of color components having saturation to be enhanced; a saturation enhancing device that enhances, based on the saturation enhancement amount determined by the saturation-enhancement-amount determining device, the saturations of the plurality of color component extracted by the color component extracting device; and an enhancement-amount adjusting device that adjusts the determined saturation enhancement amount determined by the saturation-enhancement-amount determining device when the saturation enhancing device enhances a saturation of a predetermined color component among the plurality of color components.