how do you create you image when doing Lithopains on your 3D printer

Did you use that site above for creating it?

I forget the setting in S3d that makes the extruder follow the outline of the piece rather than jumping across open areas, it helps prevent stringing. Might dial back the extruder when it changes direction a little too to get rid of the boogers.
I'll see if I can find the night light adapter I drew up, lets you place it at the bottom of the curved lithophane from that site in the slicer and print them together, so that you can clip it on a nightlight.