No, what you have done is stolen someone else’s work, and image, defaced it, and then reposted is as your own without credit to the owner. Now, that said, posting credit does not absolve you from liability even in the least. You've basically hosed yourself, and if they decide to sue, you have no leg to stand on. Why open yourself up to that? I'd remove it asap before they find out. At the very least, your Youtube account will be possibly suspended, which may be a good thing actually.