BUG: Not unsolvable, but you may end up in trouble

[Dualnames]

I noticed that if you put a -1 in the image property of an object in a room, the room ends up unusable. I was able to overcome this, by not saving the changes, but if someone somehow messed up with this, I believe it would be frustrating, even if we all know we shouldn't put minus values on object.image property.

Just thought I should mention this.

[Pumaman]

Hehe, quite unlikely to happen but I'll fix it anyway.