Features
This ornament can hang from the Christmas Tree or stand on a shelf. It can hold two 2" x 2" photos, back to back, with a space in-between them. The two photos are easy to load and won't fall out. That way, when it hangs on a tree, you don't mind if the ornament turns around. You can put small battery-powered LEDs between the pictures if you want to.
Construction and finishing
This is printed as a single piece, which is rather surprising given the voids and slots. Additive manfacturing still amazes me.
Printed at medium res with a raft and supports. I set infill to 20% and temperature to 233 degrees, but your mileage may vary.
My wife designed the photo retaining features. Photos are loaded and kept in place with slots. The slots are 2mm deep and 2" high (units are mixed because photos are usually sized in inches where I'm from, but only a masochist would model in inches). The photos don't fall out because of an overhanging rim. I was surprised by how easy it was clean out the support material - I used a steak knife and continued with fingernail sanders.
The big space between the photos is there to conserve PLA and to keep the weight down.
I've included images to show the size relative to the Replicator2, and to illustrate the process of loading and cleaning out the photo slots. It's printed in clear PLA, and the trim is painted with blue acrylic paint.
It takes 4 hours 35 mins to print on a Replicator 2.
Potential Mods
I've supplied the Sketchup file, if you want to mod (there's a tempting space under the sleeve for batteries and electonic mods, for example).
You could make the slots deeper than 2mm, so that you can slide in acrylic or plastic covers for the photos.
Of course, you could also use the basic photo frame 'technology' to produce your own frame design, or enhance your arduino box with a photo cover, for example.
I thought too, that you could use a thin PLA square in place of a photo, to use the slide design as a simple battery cover.