1. An image processing system for processing image data and displaying an image, comprising: (a) a partial enlarge unit for enlarging a part of the image so as to create an enlarged partial image; (b) a display unit for displaying the image and the enlarged partial image created by the partial enlarge unit so that the enlarged partial image overlaps the image; (c) a zoom processing unit for zooming the image displayed by the display unit; and (d) a zoom process control unit for changing a position which is a criterion in case of the image zoom processing unit zooms the image according to whether the display unit displays the enlarged partial image so that the enlarged partial image overlaps the image.