I modified the original to replace the screws with embedded magnets for a cleaner look and also easier swapping of lithophane pictures. You will need four 5x2 round magnets. The print will pause for you to add the magnets and then continue to embed them into the frame and end piece.

Update: Added a print profile to use 3 5x2 non-embedded magnets for each side so 12 magnets. This provides enough strength to hold the frame vertically with everything in it and not have the end fall off.