When writing a custom transformation for the Lightbox gallery web part, it is necessary to use the 'rel' and 'rev' parameters as highlighted in the transformation code below. The title parameter is used to determine the description of the image displayed in the lightbox.
If you would like to use multiple lightboxes on a single page, it is necessary to set a different Group name property for each lightbox web part.
Help URL: http://devnet.kentico.com/docs/webparts/index.html?lightbox_overview.htm