All right, I have saved the background as a JPEG, Then rendered the animation over the top of that background pic the forground animation was in PNG. The background again disapeared. So now I have a background in PNG, and JPEG with the overlay animation in PNG.

I would render all in one shot, but the leave in the trees in the backtground has flicker unnatural. I don't want to use the animation into after effects the renders would be very time consuming.

I am going to try rendering both background, and forground in JPEG. hope that works.