This picture frame is designed to use the backs of two CD jewel cases as panes. Your picture sits in between the two panes, allowing it to "float" in the middle without touching the edges of the frame. The holes in the back of the top allow you to hang it using a piece of string.
I chose the backs of the CD cases because they're bigger than the fronts and are less likely to have cutouts or ridges. To remove the sides, carefully score along the edges with a razor blade. It's easier to go over it lightly several times than to try to cut deeply all at once. After a few cuts, the sides should snap off easily. Watch out, it might leave sharp edges! If so, smooth them down with sandpaper or a file.
I had poor luck getting a slicer to produce useful supports, so I've included a copy with the custom supports I used. YMMV.
I originally created this as a Mother's Day gift. I've included that version as well, but I doubt many people out there will have much use for that exact frame. It's included more as a suggestion of how you can customize this thing.