Dynamic Drive’s, Image Thumbnail Viewer is a compact, unobtrusive image viewer that can be applied to any link on the page to load the desired image inside a sleek interface based on the link's "href" value. Simply give the link in question- be it a text link or image thumbnail link- a rel attribute of "thumbnail", and you're done.
This script will center the enlarged image on the page and optionally display a text description based on the activating link's "title" attribute. A fading effect can be turned on/off to bring the final image into view.
Demo: Tranquil Streets