I just wanted to say that I've also ran into a lot of problems with rendering when I've tried to use camera based image planes so I aviod them as well. I've noticed they're in a lot of beginner books, I don't really get why.

Try setting up geometry based image planes instead, there's a tutorial in the free section https://www.simply3dworld.com/movie_p...html?tut_id=64 if you need some help with it.

Hope the project goes well,
Nilla