How is iconoclasm a heresy? It wasn't condemned until the 7th ecumenical council (Second of Nicea) in 787, I don't believe there is substantial Biblical evidence to support iconophilia, and there is good reason to believe that several early church fathers were iconoclasts.
I believe by Iconoclasm as a heresy they mean the act of destroying all depictions of Jesus and other biblical figures. We know that the early church and church fathers did have images of christ and the apostles so we can definitely say that it is ok to have icons. The debate in modern times is if we should venerate icons.
Please correct me if I am wrong about this.