A single image broken up into parts, or slices. These are often used for navigation. Different areas of a single image can be linked to different pages. Image maps are fine to use, as long as accompanying text links and ample body copy is included as well on all pages.
Image maps allow you to create multiple links over the top of a single image. By apply shapes (circles, squares or polygon) you can define spatial coordinates to be "hot zones" which link users to a specified page or site.