If you’ve ever bought a picture frame for hanging on the wall and didn’t realize it didn’t come with picture frame hardware then here is a basic overview of the most common types of hardware available. There are different types of hanging hardware depending upon the type of frame you want to hang and its weight.
In most cases, wood frames are what we think of when it comes to installing hanging hardware. 
That’s because metal frames have too hard a surface and therefore, must have hanging hardware already attached to the metal frame. Here is just one example of a metal frame that has a metal hanging clip that easily comes on and off depending upon what direction you want to hang your frame. So, the next thing you must consider is the weight and size of the frame.
Ready Made Frame Hardware
For most frames that you buy online or in a store, these are called ready made frames and often include hanging hardware already attached to the frame. Many of these frames have a hoop or triangular piece of hardware riveted on the back of a frame already for hanging.The most common type of ready made hanging hardware is a hoop or ring. With these all you have to do is put a nail in the wall and hang your frame. These are found on small to medium sized frames that aren’t very heavy. However, when the frames get larger in size and heavier, that’s when you generally have to install your own hanging hardware.
Alligator Hooks
This type of picture frame hardware is what is often called an alligator hook. Alligator hooks have a jagged edge and are secured to the frame by small nails. They are super easy to install and come in different sizes depending upon the size and weight of the frame you want to hang. To install them on the frame, all you have to do is center the hook on the back of the frame and place a nail on each side of the hook. Super simple. Alligator hooks are generally designed for solid wood frames that range in light to medium weight.
Screw Eyes
This type of picture frame hardware is a little harder to install but is designed for larger and heavier frames. Screw eyes are screws with a circle like end that is designed to hold a wire. To install them you put a screw eye on each end of the frame and then connect the two screws eyes with picture frame wire. Here is an example of how the screw eyes are used. As you can see when you string the wire between both screw eyes, you want to securely wrap the end of the wire around each end to make sure the wire won’t slip off.
Just remember that anytime you install frame hardware yourself, remember to size the hardware to the frame you’re hanging. So, if you’re hanging a small frame, then you can use smaller hardware and smaller nails or screws. Whereas, for large heavy frames you want to use frame hardware that’s designed for the extra weight. Also make sure that the length of the screw or nail is appropriate to the thickness of the frame as using too long of a nail or screw can badly damage or even ruin your frame.