I'm developing a piece of software that will be available under AGPL license. It is a webpage intended to be used by different fandoms to track interviews with their favorite author/creator.
I'm quite certain that the content handled by the software (pictures from meetings, recorded interviews etc.) is not "infected" by the websites AGPL license and different copyrights apply to them.
However, I'd like to know, if someone wants to use a background image on this webpage, let's say a painting he or she made, would this image become AGPL licensed too? If so, is there a way to prevent it?
Would giving the webpage administrator a way to upload images to be used as backgrounds create enough separation from the software, that the license wouldn't cover those backgrounds?
I guess what I want to ask, is how to define a safe border to stop AGPL propagation over pieces of a website?