You mentioned the wall is next to the door. Is the door footprint itself part of the issue?
You had mentioned moveobjects on, but not in what capacity. If the door is potentially the issue, I would suggest to remove the door, place the picture where you want, then use MOO to replace the door.
At the least, if the picture still isn't snapping in place on the interior wall, you know it's not the door.
(This is from experience, diagonal walls and doors are problem children for me.)