Often, the fingers on the hand are separated into to groups. One group has three fingers and the other group has two.
The three fingers refer to the Blessed Trinity and the Two fingers refer His two natures, Fully Human and Fully Divine.
**Anyway, here is an excerpt of an excerpt from a blog on icons and their artistic meaning.
What does this hand gesture mean in Icons?
Posted on May 26, 2011
Close-up of Christ's Icon
This is an extract from a longer post about the Icon of Christ, but deserves a separate entry. It explains the meaning behind the way Christ and the Saints are sometimes shown holding their right hand in icons, as shown in the picture above.
To any Orthodox or Catholic Christian, Jesus’ right hand in Icons is unmistakably shown as being raised to give a blessing. The arrangement of the hand is repeated by clergy when blessing others and so the Saints in icons, if they were clergy, often hold their right hand in the same way.
Symbolism of the Blessing
The fingers spell out “IC XC”, a widely used four letter abbreviation of the Greek for Jesus (IHCOYC) Christ (XPICTOC). It is by the name of Jesus that we are saved and receive blessings: “At the name of Jesus every knee should bow, of things in heaven, and things in earth, and things under the earth;” (Phil 2:10).
The three fingers of Christ – as well as spelling out “I” and “X” – confess the Tri-unity of God: Father, Son and Holy Spirit. The touching finger and thumb of Jesus not only spell out “C”, but attest to the Incarnation: to the joining of divine and human natures found in the body of Jesus Christ.