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The Graphics Interchange Format (GIF) is a bitmap format developed by CompuServe in the late 1980s. It supports up to 256 colors and lossless compression. GIFs are widely supported by web browsers and can provide clarity and efficiency for simpler images. The format also supports animation and LZW compression. The use of GIFs became controversial due to a software patent owned by Unisys, but the patent expired in 2003.
The Graphics Interchange Format (GIF) is a computer file format used for simple images and animations. It was developed by CompuServe® in the late 1980’s and has grown in popularity with the proliferation of the Internet. GIF is a bitmap format that supports up to 256 colors and a form of lossless compression that reduces file size without losing image quality. GIFs became a source of controversy in the mid-1990s when a company tried to enforce a software patent related to collecting license fees.
File formats dedicated to pictures and images have been around since computers became capable of displaying them. As technology has evolved, new formats have been created to add new features. The graphics interchange format specification was first released in 1987 by CompuServe®, a US Internet service provider. Prior to this, most image formats were limited to black and white and were not optimized for Internet transmission.
GIF was the first image format to be widely supported by web browsers and has remained popular online despite the introduction of new formats. The GIF format isn’t particularly suited to photographs since it can only support 256 colors, but it can provide both clarity and efficiency for simpler images like illustrations or logos. The second revision of the format, GIF89a, supports transparencies. A fairly unique feature of the graphics interchange format is its support for animation. You can save multiple GIF images within a single file and play them in sequence, just like a roll of film in a movie projector.
Images created using the graphics interchange format are saved in what is known as a raster or bitmap image format. This means that the format contains information describing the width and height of the image and where individual pixels belong in that image. The other type of image format, vector graphics, saves images in a mathematical format that describes how an image on a screen should look like. Vector images, unlike bitmaps, can be scaled without loss of quality, but are much more computationally complex.
Like many of the image and graphics file formats used on the Web, GIFs are compressed to reduce file size and allow for faster transmission over the Internet. Some formats, such as the Joint Photographic Experts Group (JPEG) format, use lossy compression, which reduces the file size of the image while decreasing the image quality. The graphics interchange format uses a form of lossless compression called Lempel-Ziv-Welch (LZW), named after the three men who developed the technique. LZW compression uses a mathematical algorithm to compress and decompress the data within a file, thus resulting in smaller file sizes without any loss of quality.
The use of GIF images became controversial when it was revealed that the format was subject to a software patent owned by information technology company Unisys®. The patent did not apply to the image format itself, only to the LZW compression used by GIF. Unisys® announced in late 1994 that it expected users of LZW compression, both for GIF images and other file formats, to pay a license fee. Some web masters feared that the company would try to collect royalties from any website using GIFs, and the Portable Network Graphics (PNG) format was created as a patent-free alternative. PNG images did not become the instant success some had hoped for; in 2003 the Unisys® patent on LZW expired, which means that both formats can now be used freely.
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