GIF –acronym for Graphics Interchange Format – is a digital image format that can be used across all platforms and connections of varying speeds.
GIF is a compressed, lossless format developed by Unisys for CompuServe. All images created in this format have the file extension ‘.gif’. When Unisys decided to enforce its patent on the compression algorithm used for the GIF format and commercial developers of GIF images (but not users) faced royalty payments, PNG (Portable Network Graphics) was developed as an open source format. PNG format scores over the GIF in that its compression is better and it supports millions of colors.
An interesting footnote to this story is that all of Compuserve’s patents have now lapsed and payment for GIF use is not an issue any more.
GIF format uses a compression ratio of between 3:1 and 5:1 and has an 8 bits per pixel format that allows use of a maximum of 256 colors only from a 24- bit RGB color palette. This feature is what makes it a less preferred option over JPEG format for photographs and other grayscale images.
The best use of GIF is in icons and in small animated images where shading and realism are not issues.
GIF images look like animated movies of early days of Disney in their limited and jerky movements and a low range of colors but, unlike the movie technique, still find extensive use on the web. Some samples of the more interesting ones developed by London based Robin Davey are presented here.