Typical extensions are .jpg or .jpeg.
In order to keep file sizes and transfer times to a minimum, graphics on the Web are compressed. The two most popular compression schemes are GIF and JPEG, and each handles color and compression in very different ways. This section introduces some of the most common graphics and image file formats. It is copyrighted by Tom Hudson, which is why I have included the licenseing stuff. Line 1 has the number of parts, number of vertices, number of polygons and number of elements in the connectivity array.