four bit gray scale4-bit image

   A digital image with two bits allocated for the storage of each pixel, meaning eight monochromatic colors are possible — a see thumbnail to right gray scale (or value scale) of sixteen values. Also see 1-bit image, 2-bit image, 3-bit image, 8-bit image, 12-bit image, 16-bit image, 24-bit image, and 32-bit image.