[Is it possible for demons to manifest themselves in pictures and paneling on walls?]
When I was younger and I still do, I could make up pictures on the walls that were like that in my house. It could be just your imagination. The thing to do is to cover yourself in the blood of Jesus, and then say the name Yeshua Hamashiach out loud. If it is still there than it might just be your imagination. If it is not then it is most likely a demon. Just test to see what it is.