Today I made a mini frame out of a glass sheet from a broken table lamp. The diameter of the glass is 5,5cm.
As background I made a circular wooden sheet in the diameter 7,5cm.
To fix the both sheets I've used the original screws and metal sheets from the lamp.
The hanging system is provisional, but it works.
The picture is a 9x13cm c-print, which I cut. Now it is also circular and has got the same diameter like the glass sheet.