The lightbox2 module is a simple, unobtrusive script used to overlay images on the current page. it's a snap to setup and works on most modern browsers.

the module places images above your current page, not within. this frees you from the constraints of the layout, particularly column widths. it keeps users on the same page. clicking to view an image and then having to click the back button to return to your site is bad for continuity (and no fun!).