Hi all, what I am trying to do is have a picture wrap it self around another picture..kinda

For example say I have a picture of a car of somesort and another picture of an apple what I want to do is emboss the apple to the car. that way the car picture is the same but now there is a transparent outline of an apple in the picture. 
It's kinda hard to explain.   maybe think of it as a real photo and I press a apple shaped cookie cutter into the backside of the photo the apple shows through and the photo has the apple shape pressed into it.

any idea's on how to do something like this?
btw I'm using cs2

thanks