If you must walk in someone's shadow make sure it's your own
The figure in the icon is not meant to represent literally what Peter or John or any of the apostles looked like, or what Mary looked like, nor the child, Jesus. But, the orthodox painter feels, Jesus of Nazareth did not walk around Galilee faceless. The icon of Jesus may not look like the man Jesus two thousand years ago, but it represents some *quality* of Jesus, or his mother, or his followers, and so becomes an open window through which we can be given a new glimpse of the love of God.
Many religions have attempted to make statues of their gods very large, and the idea, I suppose, is to make us feel small. But if that's their purpose, they can keep their paltry icons. We need only look up if we wish to feel small.