2. The system of claim 1 , wherein the image portions are substantially similar in shape to the pixel blocks, but differ in size from the pixel blocks.
2. The system of claim 1 , wherein the image portions are substantially similar in shape to the pixel blocks, but differ in size from the pixel blocks. 3. The system of claim 2 , wherein the size of the image portions is a whole number multiple of the size of the pixel blocks, so that each image portion is completely made up by a whole number of pixel blocks.