Same thing has happened to me. iPhone 5S with 8.1.2. I know it was working 25th and possibly 26th. Only noticed today that the pics are gone. Not sure whether to try restoring from icloud. Did anyone manage to get the pics back with a restore? There is a thread on the apple forums too (https://discussions.apple.com/thread/6618182?tstart=0). seems like quite a serious bug in ios 8Hello
I Have the same problem.
2 days ago, I changed nothing and pictures / vidéo are gone from iMessage but still available on iMessage App on my Macbook air.
Any solution ?