Songs are okay, so long as they depict what the Bible says about God/Jesus, or else they become blasphemous.

The issue isn't just worship of images and they becoming an idol. It doesn't matter what the intent of the artist was or the thoughts of the viewer. Images of God inherently influence our understanding of God. eg Jesus as blue eyed, bearded, long hair; God the Father as bearded old man. The only thing that should influence and inform our understanding of God is what God himself has revealed to us (in this case, the Bible).

There's nothing I can do to change the fact that the last supper painting, or various crucifixion paintings, exist. People of all religions and even many non-religious people will enjoy and appreciate the artistry and skill of these works of art. What I can do, and do do, is to warn committed Christians that such images should not be meditated upon or placed in places where the church meets and not created in the first place.

BTW, I'm okay with art generally. There's nothing inherently wrong about it. But depictions of God in art are a no no.