An image display system (10) includes an image buffer (20,22) having a plurality of addressable locations for storing image pixel data. The system further includes circuitry (24,34,36) coupled to an output of the image buffer for converting image pixel data read therefrom to electrical signals for driving an image display (18). The circuitry is responsive to signals generated by an image display controller (16) for generating one of a plurality of different timing formats for the electrical signals for driving an image display having a specified display resolution. The apparatus further includes circuitry (40,42) for configuring the image buffer in accordance with the specified display resolution. The image buffer is configurable, by example, as two, 2048 location by 1024 location by 24-bit buffers and one 2048 location by 1024 location by 16-bit buffer; or as two, 2048 location by 2048 location by 24-bit buffers and one 2048 location by 2048 location by 16-bit buffer. Each of the 24-bit buffers store R,G,B pixel data and the 16-bit buffers each store a color index (CI) value and an associated window identifier (WID) value. Circuitry at the output of the image buffer decodes CI and WID values into R,G,B pixel data and a Key value specifying pixel mixing.