No one wants to wait around for a Web page that loads slowly, or fails to load completely. If your site does not respond quickly, you will lose visitors to more responsive sites.
Performance is key to the success of a site.
There are many factors that influence performance on the World Wide Web, but most of them are not in any single entity's control. You can, however, stack the deck in your favor by making sure your pages are carefully designed, and by choosing your Web presence provider wisely. You can't influence the quality and speed of their Internet connection, but you can lower the time that it takes for your pages to load. Reduce the number of colors as much as possible. JPEG is typically good for photographs and other images, while GIF is well suited to less complex images like logos and line art.