The best and most reliable option is to go for the nail and hook. It can be used in just about every frame. But if you are looking for alternatives, you can also consider Velcro or braided wire.Velcro can be used only for frames that are relatively small and lightweight. On an approximate basis, frames up to 30cm by 40cm could be hung using Velcro. As the frame becomes heavier, the more ineffective Velcro becomes. Braided wires are also an option but they can be tricky to use for hanging photo frames.