Hanging picture on a very hard concrete wall
Try using some 3M Command strips. For hooks, you can use something like these (it uses the same adhesive. I have hung pictures larger than 22 inches with the command strips and hang my (very large) on the 3M command hooks every day. These are available at Target, Walmart and most similar retail outlets.

These come off the walls easily if/when you move and instead of leaving behind a bunch of large holes, they leave the walls clean which will help you get any security deposit back. It sounds like these will be convenient in your case too. The hooks come in a variety of colors including white, clear and brushed nickel.