I'm thinking of creating a few tumblr accounts, they will be entertainment related. Now my question is: I'll fill it with screenshots and fan art and occasionally put a link here and there to drive traffic, am I allow to post fan art without crediting the one who made it? When I was on FaceBook I saw a lot of pages posting fan art, but they said "Credit goes to owner". Is that enough? Should I add a DMCA option on my tumblr? All tips are welcome. Peace.