1. A packed structure for image data resulting from a discrete cosine transform operation, said format comprising a run/size (RS) byte including a nibble of more significant bits indicating a run length from a non-zero AC discrete cosine transform coefficient to a next non-zero discrete cosine transform coefficient and a nibble of less significant bits indicating a number of bits required to quantify a nonzero AC discrete cosine transform coefficient, an AC discrete cosine transform coefficient adjacent a run/size byte, and and an end-of-block indicator.