Quote - Better yet, don't even bother.  Save the render as a PNG and add the background in Photoshop.

That's what I do, but I first  put the image on a once sided square and then set up the scene complete with background, props, figures and lights.

Then I hide everything but the background on the square and do a render. Because the background is on a square it reacts with the lights and gives more of an impression that it actually belongs with the figures and props that are going to be on top of it.

After I render the background, I save it as a .png file.

Then I hide the background and reveal everything else and do a render which I save as a .png file.

Then in Paint Shop Pro I lay the figures and props .png over top of the background .png.  Because both were rendered with the same lights, they look like they belong together.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi