The Graphics Interchange Format (pronounced "jif" of "jhif") is an image format which has become very popular for lower-definition graphics. Although not as common for large files, GIF images are very common for use as icons on websites, and for other such purposes. GIF images can contain up to 256 predefined colors using the bitmap method, which has been around since 1987. Additionally, GIF files can be created with a series of images which are automatically switched through in series, forming an animation. Another major advantage of GIF files is that they support transparency, so a logo can be easily overlaid on a colored or patterned background.