Use a stud
In both plaster and drywall, hanging heavy pictures on the studs are best for stability and long-term support. But if the perfect location doesn’t have a stud, there are other ways to safely hang pictures.
Use plaster hooks when hanging anything lighter than 30 pounds. To avoid bothering the plaster at all, go with adhesive hooks and strips for pictures less than 16 pounds.
For heavier pictures, anchors rated for plaster and gallery systems work best. That’s because, once installed, most use the plaster and lath’s strength to secure itself.