I noticed that in that last post on the iconodules, I failed to provide much by way of any quotations that might prove helpful. So, I offer a couple more citations in this post.
Here are the three anathemas attached to the horos (definition of faith) proclaimed by the Seventh Ecumenical Council, which I’ve translated from the Greek text found in Tanner’s first volume of Decrees of the Ecumenical Councils:
1) If anyone does not confess that Christ our God may be circumscribed according to his humanity, let him be anathema.
2) If anyone does not admit the Gospel narratives produced in art, let him be anathema.
3) If anyone does not salute such representations as signifying the name of [in the sense of standing in for] the Lord and his saints, let him be anathema.
Another argument worth noting is St. Theodore of Studios’ response to the dilemma proposed by Constantine V when he said: “According to the view of the Church we confess that the hypostasis of the Word became the common hypostasis of the two natures, lending the human nature subsistence in it . . . the same hypostasis of the Word is uncicumscribed according to the nature of the divinity, but circumscribed accoding to the being shared with us, having its existence not in a self-subsistent and self-circumscribed bypostasis alongside the Word, but in it. For there is no nature without concrete existence, and it is beheld and circumscribed in it as in an individual. [Antirrhetorici 3.1.22, emphasis mine, from Andrew Louth, Greek East and Latin West, though this is based on an earlier English translation].
To be sure, this does not say everything and there is much more that could be said, even beyond what was argued at the time, but I think these two citations at least lay out the beginnings of what Orthodox were arguing at the time. Those interested in reading more ought to consult the writings of Ss. John of Damascus and Theodore of Studios that have been published in English translations through St. Vladimir’s Seminary Press as part of the seminary’s “Popular Patristic Series,” currently edited by Fr. John Behr.