The Lightbox2 module can be configured at Administer >> Site Configuration >> Lightbox2. Users will need the 'administer lightbox2' permission to alter the settings.

• Use Lightbox2 Plus - Un-checking this box will enable Lightbox2 Lite. The Lightbox2 Lite option does not use the Scriptaculous/Prototype libraries and is therefore less likely to conflict with other modules.
• Enable for Image Nodes - Checking this box will enable automatic URL formatting for image nodes, for example those in image galleries and in the "random image" block.
• Enable Grouping - Checking this box will enable automatic grouping of image nodes on a page. This is quite useful for image galleries and image sets.
• Disable Lightbox for Gallery Lists - Checking this box will disable the lightbox for images in gallery lists, but will still use the lightbox when viewing gallery images. This is useful when you want to be able to click on an image to enter the gallery but you want to have the lightbox appear when you click on a image when viewing the contents of a gallery.
• Enable Gallery 2 Filter - Checking this box will enable the Gallery 2 filter.