Exodus 20:4 and Deuteronomy 5:8 make it clear that God must not be worshiped in, with, or through images that depict anything found in the creation. The only kind of "pictures" God has prescribed for us in the church, outside of the preaching of his word, are the holy sacraments: the Lord's table and baptism. However, graven images of people (and of God) not only violate his worship, but they impair and rob God's true glory in these representations through the fallible, limited, imagination and art of sinful men, as well as distract us of our pure devotion to God alone. If that last wasn't true, we wouldn't need them at all. The idea that these images help or aid us shows what's wrong with where our heart is in worshiping God. In John 4:24, we read that we are to worship God in truth and spirit, throw out those "visual aids."
Also, if the above is true, then even depicting Jesus is a form of idolatry. Even worse, Nestorianism, separating the divinity of Christ from the depictions and only representing his humanity.
If you want me to, we can address every one of John of Damascus' gross defenses from Scripture where he attempts to entangle the reader to believe that God permitted such idolatry in the land of Israel. We should make a thread about this...