Advantages of JPEG Format

There are two good reasons: to make your image files smaller, and to store 24-bit-per-pixel color data instead of 8-bit-per-pixel data.

Making image files smaller is a win for transmitting files across networks and for archiving libraries of images. Being able to compress a 2 Mbyte full-color file down to, say, 100 Kbytes makes a big difference in disk space and transmission time! And JPEG can easily provide 20:1 compression of full-color data. If you are comparing GIF and JPEG, the size ratio is usually more like 4:1.

The second fundamental advantage of JPEG is that it stores full color information: 24 bits/pixel (16 million colors). GIF, the other image format widely used on the net, can only store 8 bits/pixel (256 or fewer colors). GIF is reasonably well matched to inexpensive computer displays - most run-of-the-mill PCs can't display more than 256 distinct colors at once. But full-color hardware is getting cheaper all the time and JPEG photos look much better than GIF on such hardware. Within a couple of years, GIF will probably seem as obsolete as black-and-white MacPaint format does today. Furthermore, JPEG is far more useful than GIF for exchanging images among people with widely varying display hardware, because it avoids prejudging how many colors to use. Hence JPEG is considerably more appropriate than GIF for use as a Usenet and World Wide Web standard photo format.