The Graphics Interchange Format defines a protocol intended for the on-line transmission and interchange of raster graphic data in a way that is independent of the hardware used in their creation or display.
The GIF image format uses a built-in LZW compression algorithm. This compression algorithm is patented technology and currently owned by Unisys Corporation. As of 1995, Unisys decided that commercial vendors, whose products use the GIF LZW compression, must license its use from UNISYS. End users, online services, and non-profit organizations do not pay this royalty. Since it\'s inception GIF has been a royalty-free format. Only as of 1995, did Unisys decide to collect royalties. To avoid this royalty, vendors have developed an alternative to GIF that supports transparency and interlacing called PNG ("ping"), the Portable Network Graphic.
