1. An image processing device for processing image data, comprising: an image input portion receiving image data indicative of an image; and an image processing portion processing the image data into processed image data indicative of a processed image which has image portions easy to distinguish, wherein: the image processing portion includes an image output portion forming the processed image based on the processed image data on a recording medium, the image processing portion includes a color image processing portion processing a color state of an entire part of the original image, and the image data is indicative of an original color image having a color hue, the color image processing portion processing the original color image into a processed color image whose color hue is determined by rotating the color hue of the original color image on a predetermined color plane.