1. An image processing method for patching pixels of a digital image representation shown on a screen of a computer, the method comprising the steps of: a) reading a predetermined area to be patched on a digital image representation selected by a patch object and values of gray scale of pixels within the predetermined area; b) sorting the values of gray scale of the read pixels in a descending order; and c) selecting a value of gray scale of an intermediate index for replacing the value of gray scale of each of the pixels corresponding to the predetermined area to be patched.