Who is "Jesus Christ of the old days" icon?
This is an icon depicting Jesus with grey hair. Uncommon nowadays, but in days gone by, this imagery would have been a little more commonplace in the Early Church (olden days).
Before going on it should be noted that there is no physical description of Jesus contained in any of the canonical Gospels. But grey hair biblically symbolizes wisdom! Thus it would be fitting to see this symbolism in icons of Jesus.
It should be equally noted that a cruciform halo was worn only by Jesus (and the other persons of the Trinity), while plain halos distinguished Mary, the Apostles and other saints, helping the viewer to read increasingly populated scenes.
Incised sarcophagus slab with the Adoration of the Magi from the Catacombs of Rome, 3rd century. Plaster cast with added colour.
Except for Jesus wearing tzitzit - the tassels on a tallit—in Matthew 14:36 and Luke 8:43–44, there is no physical description of Jesus contained in any of the canonical Gospels. In the Acts of the Apostles, Jesus is said to have manifested as a "light from heaven" that temporarily blinded the Apostle Paul, but no specific form is given. In the Book of Revelation there is a vision the author had of "someone like a Son of Man" in spirit form: "dressed in a robe reaching down to his feet and with a golden sash around his chest. The hair on his head were white like wool, and his eyes were like blazing fire. His feet were like burnt bronze glowing in a furnace (...) His face was like the sun shining in all its brilliance" (Revelation 1:12–16, NIV). Use in art of the Revelation description of Jesus has generally been restricted to illustrations of the book itself, and nothing in the scripture confirms the spiritual form's resemblance to the physical form Jesus took in his life on Earth.
The appearance of Jesus had some theological implications. While some Christians thought Jesus should have the beautiful appearance of a young classical hero, and the Gnostics tended to think he could change his appearance at will, for which they cited the Meeting at Emmaus as evidence, others including the Church Fathers Justin (d. 165) and Tertullian (d. 220) believed, following Isaiah:53:2, that Christ's appearance was unremarkable: "he had no form nor comeliness, that we should look upon him, nor beauty that we should delight in him." But when the pagan Celsus ridiculed the Christian religion for having an ugly God in about 180, Origen (d. 248) cited Psalm 45:3: "Gird thy sword upon thy thigh, mighty one, with thy beauty and fairness" Later the emphasis of leading Christian thinkers changed; Jerome (d. 420) and Augustine of Hippo (d. 430) argued that Jesus must have been ideally beautiful in face and body. For Augustine he was "beautiful as a child, beautiful on earth, beautiful in heaven." - Depiction of Jesus
There is nothing wrong with depicting Jesus with grey hair. Nowadays it is not considered common.
What does the Bible say about gray hair?
Gray hair is usually a sign of aging. Although some people turn prematurely gray in their twenties or thirties, most don’t start graying until middle age. Many gray-haired people in Western societies hide the gray, but in ancient times gray hair was a badge of honor. The gray-haired were treated with respect. God commanded such demonstrations of respect in the law He gave Israel: “You shall stand up before the gray head and honor the face of an old man, and you shall fear your God: I am the LORD” (Leviticus 19:32).
Proverbs 20:29 says, “The glory of young men is their strength, gray hair the splendor of the old.” A man or woman who has lived long enough to develop gray hair has had many opportunities to gain wisdom and knowledge. Gray-headed people have lived through various seasons and experienced trials, and they have learned some things the young have yet to learn. Such experience should be honored: “Gray hair is a crown of glory; it is gained in a righteous life” (Proverbs 16:31).
Eastern icons of God the Father depicted in Orthodox Iconography are frowned on because of confusion in its imagery.
The Ancient of days
The depiction of the Father as an old man, then, is not proper if it is understood as a hypostatic icon, that is, an image of the hypostasis of the Father, for the hypostasis of the Father is only depicted by His Son. The idea of the Father is depicted via the symbol of the angel. Can the idea of the Father be depicted as an old man? Some might argue so, though the propensity for this form to be understood as a hypostatic icon is perhaps too great, and in order to avoid this confusion, such depictions are regulated as non-canonical and prohibited by the 1667 Synod of Moscow (as they are understood to be images of the Father).
The Bible itself, however, uses the image of an old man, as an eidos image in the vision of Daniel, which he sees in a vision. “The Ancient of Days was seated; His garment was white as snow, and the hair of His head was like pure wool” (Dan. 7:9). In this context, however, we are not given the impression that this image refers to the hypostasis of the Father, but to God in His unified simplicity, i.e. in His oneness (The Synod of Moscow describes this vision as being of the Son). The idea symbolized here is the eternality of God, specifically that He exists before and after the earthly imperial powers which had subjected the Jewish people.
It is possible, then, to understand these “Old Man” icons as being icons of the “Ancient of Days,” and this is one way that they have been explicitly titled in painted icons. The other title that the “Old Man” icons take is “Lord Sabaoth” or “Lord of Hosts,” which references the vision of Isaiah in chapter 6 of his prophecy. Again, this image depicts the idea of God in His unified simplicity, not in His hypostatic plurality. The One Essence of God cannot be depicted in a direct manner, but the idea of it may be referenced symbolically through these eidos icons. Nevertheless, these icons remain on the cusp of canonical permissibility, and they should be treated with caution.
May or May not God the Father Be Depicted in Orthodox Iconography?