The Greek origin of the word means "light in stone" or to "appear in stone".
Lithophanes are not any thing new they were popular in the Mid 19th century in Europe. You can go to What is a lithophane and find out more about them if you are interested in there history.

Today in this modern world there is a way to make them on a CNC machine out of a solid surface material and a software program that when you load a photo into it, it will give you the negative of a photograph and the program will give you a code to the cnc machine to cut the negative out. The dark areas will appear as high spots and the lighter areas will become low spots on the solid surface material. When light is passed through the material it becomes a three dimensional picture. It is hard to believe the visual effect of the photograph. You can put them on a window and see the photos or a box is made with a fluorescent light in it as the light source.
Most Photographs work as a lithophane and the most economical