An interesting problem is the coding of palettized images. While the palettization process offers some compression (typically 3 : 1), this is usually significantly lower than what is attainable with other image coding schemes. Smoothness assumptions are typically invalid for color mapped "image" data. Therefore, normal coding schemes are inapplicable unless the images are remapped to full color images before coding. Recently, Wu [322] has suggested a new YIQ palette architecture that uses joint VQ of spatial and color information to obtain modest compression ratios. A more aggressive coding scheme for palettized images has been suggested in [323], where the colormap **data** is locally reorganized to obtain smooth blocks, and DCT coding is then utilized. Lossless entropy coding schemes have also been presented recently in [324] and [325].