Or you can just do 'Fade Paste,' if you fade it enough. I
just found that out. I'll try the Opacity thing, too.

"Fading." Is that was it's called? I always referred to it
as "ghosting" a picture.

First you paste the image you want the "background" part to
be. Then paste the image of what you want over that. Right
click and select "Paste options". You'll see one that says
"Opacity", just drag it to any level you think would work.
Then click "Ok" and you'll be able to view it. If you don't
like it, you can always choose a different level. If you do
like it, then right click and select "Validate paste".