In computing, indexed color is a technique to manage digital images' colors in a limited fashion, in order to save computer storage, while speeding up display refresh and file transfers. It is a form of vector quantization compression.
When an image is encoded in this way, color information is not directly carried by the image pixel data, but is stored in a separate piece of data called a color lookup table (CLUT) or palette: an array of color specifications. Every element in the array represents a color, indexed by its position within the array. For color information, each image pixel then specifies only its index into the palette.