Hello and Welcome to my Tutorial for Working Paintings. (It also Works for any Props) For Whose are new to Mapping.
1. Make an Entity with Entity Tool. 2. Tie the Entity to "prop_physics_multiplayer". 3. Go to it's Properties and Choose World Model and Click Browse... 4. Either Search for "painting" or "picture" in the Model Browser and Pick your Favorite one. 5. Hit OK and go to the "Flags" Tab in Entity Properties. 6. Enable (Check) these Flags:
---Start Asleep (don't fall to ground) Makes the Painting to Stay on the Wall and Don't drop to the Ground until Damaged. ---------- ---Debris (Don't Collide with the Player or other Debris, Don't fire Triggers) Optimal, Makes the Painting to not Collision with the Player, But I suggest you to Check this or the Painting might Get Buggy Sometimes.)
7. Move your Painting model Close to wall, But Leave a Gap between it, also Rotate it a Bit so it Looks More Realistic.