Make a copy of the image on a new layer. Lock the bottom layer of the two. Select the copy layer.
Use the pen tool in path mode to trace around your body in the picture on the copy layer. Try to be as precise as possible, but it does not have to be perfect. You wont see the line in the end. When the line is closed, the path will turn into a selection.
On the layer palate click the PATH tab.
On the bottom of the path tab click "make selection from path". From the Selection menu, click Invert selection. Delete the selection.
Make a new blank layer on top of the locked background layer. Select this new layer.
On that blank layer, put your wings. where they should be.
Merge layers.
Save as .jpg
Done.