The Graphics Interchange Format (GIF) was initially developed in 1987 as a solution for efficiently compressing and transmitting images over slow internet connections, which were prevalent during that era. Over time, the GIF89a specification has become an established standard within the World Wide Web Consortium (W3C).
A GIF file is composed of a series of data blocks, with the first two blocks having a fixed length and format. Subsequent blocks possess variable lengths and are self-descriptive, featuring a byte that identifies the block type, followed by a payload length byte, and finally the payload itself.