This is what I have, I did the following effect by following the steps in this post:
How do I make this image in image effect?
Now what I am trying to do is instead of having the background in the back (in my case, the green city scape, I just want it to be transparent.) Is there a way to accomplish what I want? I tried erasing the bottom layer to make it transparent and make the top layer mode "lighten" but it doesn't do anything. I have some examples of what I am trying to accomplish if you scroll all the way to the bottom(they are the closest things I could find).
Here are some examples to sort of paint a better image of what I want. Don't be fooled by the Al Capone example (I don't want it to be cartoony, it's just an example).