What actually happened was...:
I re-created a map in snapshot 13w39b from a very old map (minecraft 1.2)
When i spawned in i could see item frames had spawned up in the air above me.
I could not interact with these frames at all. they were there but i could not brake them or anything.
Later the same day i created a brand new map within the newest snapshot and then picture frames had spawned in above my spawn point.
again they were there but i could not interact with them in any way other that looking at them.
Steps to Reproduce:
I tried to re-create the maps with this bug on using the same seed several times and the frames were there every time i tried.