A wonderful page describing the history, purpose and content of Orthodox iconography:
ICONOGRAPHY IS THE ORIGINAL TRADITION of Christian sacred art, and has been an integral part of the worship and mystical life of Christians since apostolic times. Referred to in the Eastern Christian tradition as “windows into heaven,” they have inspired and uplifted millions of the faithful, and have at times been the instruments for demonstrating God’s miraculous intercession in the life of mankind.
Despite my status as full-time iconoclast, I must admit to a long-standing affinity for this particular form of imagery. I’m not drawn to worship or even venerate the personages preserved in these pictures, but I am drawn to the love and devotion poured into them by their creators.
And the icons do seem to beam out some sort of juiced-up spiritual energy, don’t they?
One thing I didn’t know: St. Luke is considered to have been the first iconographer, when he painted the Virgin Mary and obtained her blessing. Apparently at least five of these images are still revered today, 2000 years later.