There are many ways to hang a picture, but using picture wire works well. Consider the weight of the picture as well as the material of the frame. Wood and metal frames may require different wire hangers, though generally any frame hanger works for either as long as the screws are appropriate for the material. Heavy frames require sturdier hardware and heavier gauge wire. Variations exist, but the basic hanger is a small metal strap with a hole for inserting a screw on one end and a loop on the other end for attaching picture wire.
Measure down the back of the frame from the top 5 cm (2 inches).
Mark that position on each side of the frame.
Drill a hole very slightly smaller than the diameter of the metal screws you will use to mount the hanging hardware to a metal frame. Skip this step if you are using a wooden frame.
Position a simple hanger on each side of the frame and attach a sheet metal or self-threading wood screw through the hanger on each side using a screwdriver.
Measure the distance between the two loops of the hangers and add 7.5 to 10 cm (3 to 4 inches) to that number. Cut your picture wire to that length.
Thread about 2.5 cm (1 inch) of wire through one of the hanger loops and wrap it back on itself several turns with fingers or pliers to secure it. Repeat with the other hanger.
Ensure that the wire has slight give in it but does not reach above the top of the frame when pulled up tightly in the middle.
Hang your picture.
For large frames, purchase hangers with two or more screw holes and use heavy gauge wire. Picture wire comes as braided galvanised steel or a cable-like stainless steel. It is standard to express gauge size as #2, #3 and so on -- each number corresponding to a specific weight limit it can support. For example, #9 stainless-steel wire supports 45.4 kg (100 lbs), while #2 braided wire is rated only for up to 5.44 kg (12 lbs). Use the correct size wire for best results.