Hold the picture up to the vinyl siding. Move the picture around until you decide where the best position for it is. Mark the center of the top side of the picture on the siding with a pencil. For pictures that weigh more than 5 pounds, mark the points 2 inches from the center on either side.
Hold the siding hook so the smaller hooked end is facing up. Slide the hook under the vinyl siding above where your pencil mark is, until you hear a click. Pull down on the hook to ensure it is fastened tightly in place. If you have two pencil marks, repeat the process with a second siding hook.
Fasten a piece of string to the back of the picture between the picture hooks, if there is no string to hang the picture from already. Lift the picture up and place the string over the larger hook portion on the bottom of the siding hook. Adjust the picture until it hangs straight.