Abstract: A compression and de-compression arrangement is provided for a display device having a display memory and a display. The arrangement includes a colour processor which reduces the colour samples by processing a pair of pixels to produce first and second luminance values and forming first and second output chrominance values from the pair of pixels. The first and second output chrominance values are formed by calculating for each pixel the corresponding U and V chrominance values and forming the first and second chrominance values (U, V) from the average of the values for each pixel. Forming the compressed representation of the colour image provides an advantage when recovering the original image, particularly for example where the image contains detail and/or text. The image processing apparatus of the system receives the group of colour component signal samples from the display memory and generates first and second output pixels, each comprising three colour component values (R, G, B), from each group.