Into combution
How to set it as a multiply layer
I have imported two images. (Normaly these would be image sequences but the same tech will apply)
I have placed the wire layer on top, so that it is showing in the composit node.

Double click on the wires transform node. (that would be the circle under the wire footage)
Click on the layer button and it will bring up this menu. Click on "Normal" and select "Multiply"

This is the image you should get. (same as if you were doing it in photoshop) My solid image has no smoothing so it might look a bit wierd
I find that I sometimes adjust the opacity for looks.