Game content IP usage for games with unofficial Books/SRD's question.

Hi, I wasn't sure where to post this question, but with it covering "Creative Content" in its name, I figured I'd try here. My friends and I would like to play a private, non-commercial game, using one of Roll20's systems/sheets. As I was reading up on the content, it came to my attention that the creators of the Handbook do not own the rights (PTA3 is the game system we want to use) to the content involved. After reading the "terms of service", I was unsure if by uploading images (even AI-generated, if needed) into my art library on the campaign, if I would get in trouble with copyright infringement? 

I doubt that there would be any problems using art or any other resources as long as it's a private game, but I'd post your question here to make sure.

I am pretty sure as long as not monetized in anyway or streamed, purely for private use, you should be fine, but follow what Rick posted to be on the safe side. :)