Graphics Interchange Format. A compact image format developed by CompuServe that displays up to 256 colors. It works well on website graphics such as cartoons or line drawings that use only a few colors. Later new features were added in GIF89a that enabled animation, interlacing and transparency.

A smooth progression from one color or tone to another involving two or more colors.

A continuous tone image comprised of grays from white to black. In printing, a grayscale image is made up of only black ink. The value of gray is defined by the density and size of the black dots printed.