1. A method for compensating images in a display device, the method comprising: calculating distortion ratios of image blocks based on a gray value difference between each of a plurality of pairs of pixels in the image blocks that face each other at a boundary between the image blocks; setting compensation parameters based on the calculated block distortion ratios; calculating distortion compensation values of the image blocks based on the gray value difference and the set compensation parameters; and compensating the image blocks according to the calculated distortion compensation values.