Ever since I first saw a lithophane in a YouTube video I have thought they were really cool.  I have made cylindrical lithophanes previously with my CNC machine.  When I bought my 3D printer I thought I would give printing lithophanes a shot.  I tried working lithophanes into Christmas ornaments with marginal success (See some of the ornaments here).  After a little refining I printed some pictures on a cylinder and a night light cover.  I removed the original night light cover and replaced it with a 3D printed version.  The nightlight worked out well since it was a purposeful back light for the lithophane.  Below are some pictures of the results.  The cylinder is back lit by a battery operated tea light candle (the pictures are the front and back of the same cylinder).  I spent a bunch of time making the STL file only to find that there are utilities that other people have made available for making cylindrical lithophanes.  Here is a link to one I found on Thingiverse: Customizable Cylinder Lithophane Lamp.