Paste a picture as a new image and cut it out with the lasso tool, which is hard to find. It is under the Box option click the arrow thing next to it and it is the third thing down and it looks like a circle but a little bump on the end. You dont have to cut it perfectly because then you can use the eraser to clean up the edges (to adjust the size go to adjust brush size on a thing that comes up on the side). when you have it good take the move tool and click on it and copy and paste as new layer on your sig. Then you can clean it up some more with the eraser because what you erase will show the pic underneath it.