Frederika Matthewes-Green has an essay on her web page dealing with iconogrpahy.
Here is a snippet I love from the conclusion.
An icon is meant to be a “window into heaven,” showing us, not characters as they were on earth, but as they are now, transformed by God’s glory. Every icon is an icon of Christ. If it depicts a human saint, it is showing the person as she is with Christ shining fully through her. It is our goal and destiny as well, to become bearers of this glory, and be likewise transformed. It has been said that God was the first iconographer, since we are living images of him: “Then God said, ‘Let us make man in our eikon” (Gen. 1:26). If an icon does not assist us in recovery of that union with God, it is not a true icon at all. ... “In the final analysis, icons serve a purpose only to the extent that they assist us in becoming icons of God.”Did you catch that? Icons are not painted of external reality, but of spiritual. St. John the Baptist, for example, is painted with wings, because he was the greatest prophet of them all, God's messenger, and the word "messenger" in Greek is angelos, angel. Women saints who started out as prostitutes are painted with long hair showing, even though in public they probably hid their hair like chaste women. Martyrs are depicted holding small crosses in their hands, whether or not they ever literally held one.. And so forth.
Well, when reading the story of Adam and Eve in the garden of delights, featuring a talking serpent, a Tree whose fruit could give a person immortality and another tree whose fruit could impart the knowledge of good and evil -- it helps greatly to remember that this is an icon. Yes, a verbal icon.