This is a two pieces support, combine them and you are done. The max supported frame size is: Height 22cm Width 17.5 cm Length 1.8 cm You may have to scale this from 100% to 1000% in your slicer before printing.
Folding Picture Frame Stand by David@3DOMEngineering
picture frame stand 3D Models to Print - yeggi
Free STL file Picture Frame Holder 🖼️・3D printing model to
Folding Picture Frame Stand by David@3DOMEngineering
photo frame stand 3D Models to Print - yeggi
picture frame stand 3D Models to Print - yeggi
Frame Stand Files / Wood Display stand / Sign Holder 33
Simple Standing Photo Frame by linz.designs
picture frame stand 3D Models to Print - yeggi