Computer Graphics file formats are about 'How do I save my design to disk so other programs can load it?'. The format you safe an image in must be chosen carefully, as the file format does not only influence the number of programs that are able to read an image, but also affects file size and image quality.
For the World Wide Web, two graphics file formats are dominant: GIF and JPEG (or short: JPG). These and their uses are described in the paragraphs below.