A method of processing image data comprises processing a frame of image data comprising a plurality of pixels, each having corresponding pixel values. Each of the pixel values include a first and second set of bits that may be separately or simultaneously accessed and/or processed. The first set of bits may correspond to the more significant bits of each pixel and the second set of bits may correspond to the less significant bits. In some examples the number of bits in each of the first and second set of bits may correspond to the width of a used data bus and/or features of a peripheral device connected to the image processor, such as a display.