The prints from the OpenPress Print Exchange are 7x7 cm. Hard to find frames that fit.
OpenPress never published the files for their frame design. I remade theirs and a second “floating” style frame. That one comes with an inlay to give it some depth if you are using a bright color.
There are three mounting options. There is a cutout to hang it on a nail (or very small screw) in the wall. It also comes with a bracket that slots in the back. and there is a 3mm hole that you can fit a M3 screw in.
The original frame can be bought at: https://openpressproject.com/collections/ebooks/products/mini-picture-frame
If you want prints of the floating frame, get in touch.
The author marked this model as their own original creation.