To be honest this is the reason I bought a 3d printer. We spent a lot of money on ceiling lights just to hear the glass break after a few minutes from installation. We got scared that glass would fall, break on the floor and cut our kids so I proposed the idea to my wife to buy a 3d printer and print our own lights in the house. These are among the very first prints and 3d designs I made.

The lithophanes can be made here https://tool.itslitho.com/CreateModel , you upload a picture and select parameters of the frame. The settings I used at “SHAPE OPTIONS” were 150mm height, 150mm width for the 4 sided light and 210mm width for the 3 sided one. Depending on your filament type, you could use the standard max thickness or reduce it to 2.8mm. I highly recommend using some matte white for the lithophane, silk type filaments diffuse the picture but that effect can be used depending on your needs. Enable Crop to change the dimensions freely. “FRAME OPTIONS” should be changed to 3mm depth.

The best results I got printing the frame that holds the lihtophanes is placing the vertically, relatively near to each other in sets of 3 or 4 with supports overlapping so they form a unified structure. That way there's little chance it will unstick from the bed or wobble while printing.

I used just 2 small points of hot glue to fix the lithophane pictures to the frame and it's better to insert the frame into the holder BEFORE you glue the pictures to the frame.