Encaustic painting, Image size 30cm x 30cm x 5.5cm Hang as a "tablet" - no frame or glass necessary.
Hot encaustic wax is a medium, used in ancient Egypt and Rome. I find that embedding my collages in this amazing lustrous medium, enables me to present the works without glass, and most of these are hung as a "tablet" directly onto the wall.
Do not hang above a radiator or in full sun. Buff with a soft cloth every month or so, to retain the sheen.