See: History of Icons
We kiss an Icon of the Blessed Virgin as the Mother of the Son of God, just as we kiss the Icons of the Saints as God's friends who struggled against sin, imitating Christ by shedding their blood for Him and followed in His footsteps. Saints are venerated as those who were glorified by God and who became, with God's help, terrible to the Enemy, and benefactors to those advancing in the faith -- but not as gods and benefactors themselves; rather they were the servants of God who were given boldness of spirit in return for their love of Him. We gaze on the depiction of their exploits and sufferings so as to sanctify ourselves through them and to spur ourselves on to zealous emulation.
The Icons of the Saints act as a meeting point between the living members of the Church [Militant] on earth and the Saints who have passed on to the Church [Triumphant] in Heaven. The Saints depicted on the Icons are not remote, legendary figures from the past, but contemporary, personal friends. As meeting points between Heaven and earth, the Icons of Christ, His Mother, the Angels and Saints constantly remind the faithful of the invisible presence of the whole company of Heaven; they visibly express the idea of Heaven on earth.
The text on this page has been extracted from The Orthodox Christian Page.