The work of present-day iconographers
To be an iconographer is a big responsibility. To Eastern Orthodox believers icons are not just 'religious pictures' but sacred images which must be treated with veneration and devotion. By doing this we express our respect and love for Jesus Christ, His Mother, and the saints.
The main function of an icon is to be an 'aid' to prayer, private or liturgical. An icon is a focus for the devotee's concentration, a window into the supernatural world, an organic part and participant of the Liturgy. To fulfil this role an icon must be free from any impurity. This may be achieved by an iconographer, firstly, by strictly following the Canon, the symbolic language of iconography which has developed over the generations by saints and artists (who often were monks and artists at the same time) in accordance with Christian theology. The Canon includes those subjects approved for depiction and, not less importantly, the way they may be depicted. The Canon is a part of the living Church Tradition, which is as important as the Scriptures.
Secondly, an iconographer must try not to bring his or her own passions and impurities into the work. This may be achieved by following the rules which the Eastern Orthodox Church has prescribed for iconographers. These rules include an ascetic life of fasting and prayer, active participation in Church Sacraments, and humbleness of spirit. An iconographer, although they were always very highly respected in the Eastern Orthodox Church, must clearly understand that she/he is just a vessel, a tool through which an icon may be created by the Holy Spirit. The talent and knowledge of the necessary craftsmanship are very important, but they are secondary.
Hopefully what makes an icon a 'true icon' is now clearer. Some people simply equate an icon with a picture painted on wood and plated with 34 karat gold leaf. Although most icons are painted by such traditional means (although, there are plenty of legitimate icons carved on ivory, wood, painted with acrylic, etc), these features by themselves do not make them 'true icons'.
Ref: http://www.orthodox-christian-icons.com/