The actual Graphics Interchange Format (GIF) is a bitmap image format that was introduced by CompuServe in 1987 and it has since come in to widespread usage on the internet due to it's wide support and portability.
The format supports up to 8 bits for each pixel thus allowing just one image to research a palette of up to 256 distinct colors. The colors are chosen in the 24-bit RGB color space. It also supports animations and allows a separate palette of 256 colors for every frame. The color limitation makes the GIF format unsuitable for recreating color photographs along with other images with continuous color, but it is well-suited for simpler images for example graphics or logos with solid areas of color.
GIF images are compressed using the Lempel-Ziv-Welch (LZW) lossless data compression way to reduce the file size without degrading the visual quality. This compression technique was patented in 1985. Controversy over the licensing agreement between your patent holder, Unisys, and CompuServe in 1994 spurred the development of the Portable Network Graphics (PNG) standard; since then all of the relevant
CompuServe introduced the GIF format in 1987 to supply a color image format for their file downloading areas, replacing their previously run-length encoding (RLE) format, which was black and white only. GIF became popular because it used LZW data compression, which was better than the run-length encoding that formats for example PCX and MacPaint used, and fairly large images could therefore be downloaded in a reasonably short period, even with really slow modems.
The original version of the GIF format was called 87a. In 1989, CompuServe devised a good enhanced version, called 89a, [1] which additional support for computer animation delays (multiple images in a stream were already supported in 87a), transparent background colors, and storage of application-specific metadata. The 89a specification also supports integrating text labels as text (not really embedding them within the graphical data), but as there is little control over display fonts, this feature isn't widely used. The two versions can be distinguished by taking a look at the first six bytes of the file (the "magic number" or even "signature"), which, when interpreted as ASCII, read "GIF87a" and "GIF89a", respectively.
GIF was one of the first two image formats popular on Web websites, the other being the black and white XBM. [citation needed] JPEG came later with the Mosaic browser.
The feature of storing multiple images in a single file, accompanied by control data, is used extensively on the internet to produce simple animations. The optional interlacing function, which stores image scan lines from order in such a fashion that a partially downloaded image was somewhat recognizable, also helped GIF's popularity, [citation needed] like a user could abort the download if it was not what was required.
