Are posters sinful?

I love music, I own tons of vinyls, CDs and posters of my favorite singers. Is it idolatry if I hang up some posters of my favorite bands? Because the doubt struck my this morning when I hung up a The Smile poster I got at a record store. I already prayed to God and told him that I worship him and him only, and that the posters in my room are nothing but decorations related to some of my interests (if it's disrespectful to pray like this then please tell me).