It’s a good idea to check the previous posts… you can find an answer to the same question much of the time. This is a quote from Matt Rhodes taken from down the page a little
” In version 3 of ProAnimator, the background is for alignment/placement only. It does not get rendered into the final output.
In version 4 (coming soon!), you are given the option to composite the background image into the final rendering. ”
JD