Background Instead of Overlay
In addition to the Vegas Background as a slider, we can also use it as the opposite of a lightbox overlay. With any display widget that supports a lightbox overlay, select the Vegas Background 'overlay'. Now clicking an item in the slider or gallery changes the background.
You can do this with a full page background as above, or direct the image to show in a block.
Click any of the images above to change this page's background.
Other details are similar to the Vegas Background slider example.