Image maps allow the user to access different documents or HTML sites by clicking on designated areas of an image using graphics. There are two ways to make and use image maps. This type of map relies on a CGI script residing on a server to process the information. This type of map works in a manner similar to HTML anchors and is processed locally by your browser.
Maps can use any kind of image source from photographs to computer-generated designs.
Although the JPEG format gives a better quality image and can be used, not all browsers are capable of supporting inline JPEGs. There is nothing like dialing in with a modem, waiting for a great page to download, only to have your connection terminated. Please try to be a conscientious Web page designer and make you pages user friendly. You need a reasonably sized GIF image for your map. This attribute indicates that the document is a client-side image map.