A little more internet searching found the trick for me. The line I ended up with is
Code:
echo "<img src='data:image/png;base64,".base64_encode($combined)."' />";
And that did it for me.
I'm probably not going to modify the script that I have at the above provided link (sorry). I'd be too afraid that someone might get the impression that I'm hosting the images rather than merely linking back to playb0y for them.
I think I will put a link on the index page for them back to here to show others how they might be able to do it (if you don't mind).