1. A method of processing image data representing an image, the method comprising the steps of: storing the image data in a memory device including a plurality of memory locations; generating a first set of row pointers and a first set of column pointers used to represent a first image, each row pointer in the first set of row pointers identifying a different one of said memory locations where data from a row of pixels is stored in the memory device, each column pointer identifying one of said memory locations where data from a column of pixels is stored in the memory device; and generating, to represent a second image, a second set of row pointers and a second set of column pointers, at least some of the second set of row pointers identifying the same memory locations as the first set of row pointers; and storing both the first and second sets of row pointers and the first and second sets of column pointers in the memory device, so that the memory device includes at least two sets of row and column pointers each of which include pointers to at least some of said memory locations used to store the image data; and wherein the memory locations defined by the second sets of row and column pointers collectively represent a virtual image, the virtual image corresponding to a region of the memory device which stores regularly-spaced image data.