GIF

The Graphics Interchange Format (GIF) is a bitmap image format developed by CompuServe in 1987. It provides lossless data compression and portability across platforms. GIF files store images as indexed color data using a palette of up to 256 colors per frame, and they employ the Lempel-Ziv-Welch (LZW) compression algorithm to reduce file size.

There are two early variants, GIF87a and GIF89a. GIF89a, published in 1989, added support for animation, transparency, and interlacing, enabling the use of multiple frames within a single file and progressive rendering.

Animation in GIF is achieved by sequencing frames, each with its own duration (delay) and optional local color table. A disposal method indicates how the next frame should be composited. The format also supports transparency through a color index and interlaced rendering.

GIF achieved widespread web use due to broad browser support and small file sizes for simple graphics. However, it is limited to 8-bit color and is not ideal for photographs. For color-rich images, formats such as PNG are preferred; for video-like animation, formats like WebP or APNG offer more modern alternatives. LZW patents held by Unisys affected usage until their expiration in 2003.

Today GIF remains popular for short looping animations and memes, and it persists as a standard graphic format supported by most devices and software.

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