A GIF image palette holds at most 256 colors.

GIF normally describes pixels through palette indexes rather than storing a full red, green, and blue value for every pixel. An index points to a color table entry, allowing compact representation when an image uses a small collection of colors.

An eight-bit index has 256 possible values. Each selected table entry can specify a color from a much larger RGB space, so GIF is not restricted to one universal set of 256 colors. The restriction concerns how many entries a particular table can contain.

Animated GIF files may use different local color tables for different image frames. This makes the familiar claim that an entire GIF can contain only 256 colors misleading. Each table remains limited, but a sequence can collectively display colors drawn from multiple tables.

CompuServe introduced the Graphics Interchange Format in 1987, when moving images between different computers and across slow network connections posed practical problems. A palette-based format suited many illustrations, charts, and computer graphics of that period, which often used relatively few distinct colors.

GIF compresses its indexed image data using LZW, a lossless dictionary-based method. The compression stage can recover the supplied indexes exactly. However, converting a full-color photograph into a limited palette may already discard color information before compression begins. Calling GIF compression lossless does not make that earlier conversion lossless.

The later GIF89a specification included features that helped the format become familiar on the web, including transparency and animation controls. Transparency designates a palette index as transparent rather than assigning every pixel an independent level of opacity. Consequently, GIF does not offer the smooth partial transparency available in formats supporting an alpha channel.

To approximate colors missing from a palette, image software may apply dithering. It arranges available colors into small patterns that blend visually at ordinary viewing distances. Dithering can make gradients seem smoother, but it may also introduce visible grain and complicate compression by reducing repeated patterns.

Animations bring another subtlety: an image frame can update only part of the logical canvas, and disposal rules affect what remains visible. Combined with local palettes, that means the displayed canvas can be more complicated than a single standalone indexed picture. The precise, useful rule is that an individual GIF color table has no more than 256 entries.

For simple looping graphics, GIF remains broadly recognizable and easy to share. For photographs, long clips, or smooth transparency, other formats often offer better results or smaller files. A format decision should consider motion, detail, browser support, and actual output size rather than relying only on familiarity.

GIF’s palette limit belongs to the representation of color, not simply to the size of a compressed file. Comparing GIF with PNG and JPEG makes that distinction useful: a lossless compression stage can preserve indexes perfectly even when preparing those indexes has already reduced the colors in the source.