What hardware would you recommend to use to hang metal tiles on a wall?

I have a bed with no headboard and I'm going to attempt to make one myself. I have twelve hammered metal wall tiles that I plan on attaching to the wall behind the head of my bed to serve as the headboard. These tiles are 12" square, they are recessed in the back and weigh about 1 lb each. They have no hardware to attach them to the wall so I'm going to have to go to Lowe's to get something. But what? The wall is painted drywall. I want these tiles to STAY on the wall and not get knocked off if my pillow hits it during the night, so just placing a nail or two and hanging the tiles probably won't work. Any suggestions? Thanks in advance! (-: