Via Abodeee.nl (Dutch website) I found a nice magnetic puzzle picture frame.
You can create your own picture frame with four magnetic photo frames. Each set consists of two black an two white magnetic photo frames which you can put together in several ways. There are sets with square and rectangle photo frames available.
The metal frame measures 9×4 cm (approx. 3.5″x1.6″) and the photo frames are 65x65mm (2.5″x2.5″) or 65x50mm (2.5″x2″).
These photo frames are available in The Netherlands and Belgium and via Dutch and Belgium web stores. Happy Puzzling!