The following picture shows how one of my very heavy doors got "skewed" in the door opening. The numbers indicate the gaps between the door and the jambs on the sides. The door used to shut perfectly, but now, apparently as a result of the sagging, the strike of the lock no longer catches the latch.
I checked the hinges and they are super tight. In fact, nothing appears to be loose. Can you help me figure out what moved, how to prevent it from getting worse, and how to fix the damage that's already occurred.
Picture of the top hinge. Perhaps it's part of the problem?