A method of comparing images is disclosed herein. The images may be represented by image data comprising a plurality of image data values. An embodiment of the method may comprise determining at least one image data value representative of at least one first portion of a first image. The method may further comprise determining at least one second image data value representative of at least one first portion of a second image. The at least one first portion of the first image and the at least one first portion of the second image are located in substantially similar regions of the first image and the second image. The at least one first image data value is compared to the at least one second image data value. The first image is similar to the second image if the at least one first image data value is within a preselected amount of the at least one second image data value.