An animated GIF is an image encoded in graphics interchange format (GIF),which contains a number of images or frames in a single file and is described by its own graphic control extension. The frames are presented in a specific order in order to convey animation. An animated GIF can loop endlessly or stop after a few sequences.
The GIF design allows users to define new blocks. In the 1990s, Netscape designed the Netscape Application Block, which indicates that the file is an animation and not a static image. This was first supported in Netscape 2.0 and spread to other browsers. It is still in wide use today.
An animated GIF is also known as a GIF89a.