What is GIF used for?

According to abbreviationfinder, GIF stands for Graphics Interchange Format. It is a graphic format widely used on the World Wide Web, both for images and animations.

History

The format was created by CompuServe in 1987 to provide a color image format for its file download areas, replacing its early black and white RLE format. GIF became very popular because it could use the LZW (Lempel Ziv Welch) Compression Algorithm to perform image compression, which was more efficient than the Run-Lenght Encoding (RLE) algorithm used by the PCX and MacPaint formats. Therefore, large images could be downloaded in a reasonable amount of time, even with very slow modems.

Characteristics

GIF is a lossless format for images with up to 256 colors, limited by a palette restricted to this number of colors. For this reason, with images with more than 256 colors (color depth greater than 8), the image must be adapted by reducing its colors, producing the consequent loss of quality.

A GIF image can contain between 2 and 256 colors (2, 4, 8, 16, 32, 64, 128 or 256) among 16.8 million of its palette. Therefore, since the palette has a limited number of colors (not limited in terms of different colors), the images that were obtained in this format were generally very small.

However, since the LZW compression algorithm was proprietary, all software publishers using GIF images had to pay royalties to Unisys, the company that owns the rights. This is one of the reasons why the PNG format is becoming more and more popular, to the detriment of the GIF format.

Applications

The use of GIFs is generally used for banner advertising. Its main diffusion today is still to display animated images for web pages, as it is the only format supported by a multitude of browsers that allows this effect.

Patents

Unisys, the owner of the patent for the LZW algorithm used in GIF format, has been demanding royalties for its use for years. Compuserve, when developing the format, did not know that the LZW algorithm was covered by a patent. Because of this, any program capable of opening or saving LZW-compressed GIF files had to meet his demands. It is necessary to emphasize that the GIF format can use other compression methodsnot covered by patents, such as the Run-length encoding method.

The 20 as June as 2003 expired in US patent for LZW algorithm.