1. An image processing system for comparing images, the system comprising: an image selection module operable to select monochromic images from a storage system; an object thinning module operable to thin objects in the monochromic images so as to generate skeleton images; an object thickening module operable to thicken the objects in the monochromic images so as to generate bold images; an image overlaying module operable to overlay the skeleton images with the bold images so as to generate overlaid images; an image output module operable to output the overlaid images on a display screen; and a processor that executes the image selection module, the object thinning module, the object thickening module, the image overlaying module, and the image output module.