Fr. Mark,
I would think that the Apostles' (and disciples') teachings against idol worship would be the strongest point. They were obeying the Second Commandment. When St. John went to Patmos, the idols fell. These idols were in the form of statues. That's just one example. Therefore, they would certainly not allow them in their churches. As for a canon, the fact that statues were never used in church since the birth of Christianity they didn't need a canon about it specifically. It was understood. Statues "fell out of favor" from the beginning.
Also, we have the Akathist of the Mother of God describing when the babe Jesus Christ fled to Egypt:
Eikos 6
Having shed the light of truth in Egypt, You expelled the darkness of falsehood; and unable to bear Your strength, O Saviour, her idols fell; and they that were set free from them cried to the Theotokos:
Rejoice, Uplifting of men. Rejoice, Downfall of demons.
Rejoice, you who trampled upon the delusion of error. Rejoice, you who censured the deceit of the idols.
However, they are not heretical because they have statues. They had statues long before the Great Schism and this was simply a point of difference between the East and West that served to fracture the Church's unity.
I just said that they got more into it after the Great Schism. Because they became heretical, they allowed statues. And of course, the heresy was a slow moving progress so, yes, they were starting to incorporate it. I don't feel the need to retract my comment, but if you can prove that statues were in the church in early Christianity, then I will be corrected accordingly.