Sadly, no.
Given the way camping works, with you going to different camp sites depending on your location. There's no real place where it makes any sense for paintings to be placed.
I mean, technically, as camp sites are persistent throughout a run, you can drop your paintings down about the place and they'll stay there whenever you go back to that particular campsite (You just have to remember to go back and pick them up if you want to move them to a new campsite)
It's one of the reasons why I would have loved if Baldur's Gate was like a central hub for the game, so we could have a persistent base of operations that we return to over the course of the game, allowing us to decorate it with things like paintings and trophies, having companions settle in and create their own spaces (Instead of just having a tent with a handful of junk scattered around) and the allies we accrue can also move in and perform their tasks and offer aid (Like vendors, companions etc).
But alas, this is not the case. We just have our many campsites and our poor old PC doesn't even get a tent to call their own in a single one...
