PICtart
It is easiest way to make your own lithophane data for your 3D printer.
It provides frames(we call it tart),
so choose and place your PICture, you can make your lithophane easily.
(PIC + tart = PICtart!)
Design & make fun things.
https://play.google.com/store/apps/details?id=com.prinpla.eggtartfree
https://play.google.com/store/apps/details?id=com.prinpla.eggtart