The trick it to keep the picture from swinging...but you also have to keep the hook stuck to the wall.
I don't like to put holes in the walls of my RV, 'cuz you can't just spackle over the hole later, so I use 3M Command hangers:
Family of Products
A hook at the top and another mount at the bottom like the ones for crafts/plaques
They are available at most discount stores. Easy on, easy off and they hold very well.
Kim and Steve, Mustang LCDR (Ret), '07 Damon Outlaw #1193
I have seen gross intolerance shown in support of tolerance, Samuel Coleridge
WE LOVE OUR OUTLAW RV