Says St. Paul: "Christ is the visible image of the invisible God" (Col. 1, 15).
Father Daniel Rousseau writes:
"Christian iconography, and foremost the possibility to represent Christ, is based on the fact of the Incarnation.(a) Just like the theologian expresses the living Truth in words by means of his thought process, the iconographer expresses the living Truth, the Revelation of the Tradition of the Church by means of his art(b). Consequently, the sacred art of icons cannot be some arbitrary creation of artists. Better than any other sacred image, the icon of Christ 'not made by the hand of man' expresses the dogmatic principle of iconography.
(This refers to the miraculous icon of the Holy Face of the XIIth century, also known as Acheiropoietos, shown to the left).
That's why the 7th Synod (787) gives it very special attention. And to commemorate the definitive triumph of the holy images, this icon of Christ is venerated the day of 'Orthodoxy'".
(Daniel Rousseau, "L'Icône, Splendeur de Ton Visage", Desclée de Brouwer, Paris, 1982, pp. 232-233.)
Here is possibly another way of saying "something similar, but not identical":
«Christian (Orthodox) iconography expresses in images the same Gospel message that Scripture communicates by words. Image and word illuminate each other»
(Source: "Catechism of the Catholic Church, Part Two: The Celebration of the Christian Mystery" paragraph 1160.)
Only "something similar, but not identical" because one might interprete the above phrase as saying «Christian (Orthodox) iconography expresses [to the unlettered] in images the same Gospel message that Scripture communicates [to the literate] by words. Image and word illuminate each other.» This interpretation might lead to the conclusion that Iconography and Scripture are identical. But they are not. Scripture cannot substitute Iconography. And Iconography cannot substitute Scripture.
«In truth there is nothing in Western Christian experience quite the same as the Eastern Orthodox Icon. It is as fundamental and essential to our theology and dogma as scripture. St. Theodore the Studite wrote: "Just as everyone, no matter how perfect, is in need of the Gospel tablet, so (does one need) the painting expressed according to it" (c).»
(The Serbian Orthodox Diocese of Canada "To the Glory of God: the Icon", 1998, http://www.istocnik.com/articles/40/eng_glory.html.)
(a) Cf. Dogma of Chalcedon.
(b) The above text is a translation from the French text by Fr. Rousseau. One might add that illumination by the Holy Spirit is a required key element for both the theologian and the iconographer to be able to express the living Truth.
(c) St. Theodore the Studite also wrote: "If contemplation with the intellect had been sufficient, it would have sufficed for the Word to come among us intellectually only"»
Virgin and Child Enthroned, ca. 850. Oldest surviving mosaic in Hagia Sophia, Constantinople. (с) trojzzza"
http://pics.livejournal.com/trojzzza/pic/002y1e67 - width=2560
"Byzantine Icons, Frescoes and Mosaics (Orthodox Byzantine Icons)
Introduction: The Essential Feature of Icons"