Icons are more than sacred pictures. Everything about them is theological. For example, they are always flat, flat so that we who inhabit the physical world will understand that the world of the spirit where Christ, His Mother, the angels, the saints, and the departed dwell, is a world of mystery which cannot be penetrated by our five senses.
Customarily, Roman Catholicism has historically employed statues in its worship. The statues are life-like and three-dimensional. They seem to imitate the art of ancient Greece. Both arts are naturalistic. The Latins portray Christ, the Mother of God, the saints, even the angels, as if they were in a state of nature. This "naturalism" stems from the medieval idea that "grace perfects nature."
The person or persons are represented on the icon as deified. He or she is not a perfect human being, but much more: They are transfigured and glorified. They have a new and grace-filled humanity.
Important to remember is the Latin theory of grace: It is created by God for man. Orthodoxy teaches, as we recall, that grace is uncreated, and impacts all creation. It is a mysterious extension of the Divine Nature. Orthodox iconography reflects this truth, even as Roman Catholic statues reflect its idea of grace.