I've been making lithos using PhotoVCarve for a couple years with excellent results. As most of you know, it can be difficult to convey the "Wow" factor of these amazing pieces using only 2D pictures.
Here are a couple videos that help visualize how the backlighting affects the litho.
"http://www.youtube.com/watch?v=7-FvhUGS-D4"]YouTube - Lithophane with backlighting from sunlight
"http://www.youtube.com/watch?v=BZiEiy4E67c&feature=related"]YouTube - Lithophane with backlighting from LED panel
The second video uses an LED panel from