Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4634058.

frame fits 98x115mm lithophane, scale to your needs use with 2x 12v strips and usb dc-dc boost boards similar to these

https://www.ebay.com/itm/DC-DC-USB-2-24V-to-5-28V-2A-Boost-Step-Up-Adjustable-Regulator-Power-ModulYJCA/303670602119

use 12v 5050 non waterproof cool white led strip, 5m is around $3-4usd from china

adjust voltage to around 10v before connecting led strips, tweak voltage for brightness

scale if needed, boost boost board holder will not fit if scaled smaller

edit: had a minor flaw, boost board does not fit properly, adjusted the pocket size and made a larger hole for the usb cable to plug into it