All these attempts a portraits of Christ are imaginary. The first is from the Catacomb of St. Callistus. (This image must be an "improvement" on the original. The author states that by his time, 1895, the original was almost gone, faded.)
This portrait is from the Catacomb of St. Pontianus.
The one on your left is from the Catacomb of St. Callistus and the cubiculum of St. Cecilia. "The nimbus, the deteriorating art, and the overloaded ornament, prove conclusively that it is not older than the fourth century."
The one on the right is from an ivory, perhpas of the early part of the fifth century.
This is an early mosaic that may or may not depict Christ. The IC could refer to the Latin for Jesus Christ. (Latin has no "J" so it uses "I".)
Frederic W. Farrar, The Life of Christ as Represented in Art, MacMillan and co. (1895) pp. 86-88.
For more see The Catacombs of Rome site, and the Catholic Encyclopedia entry on them. Also see a photo.
This web page is the responsibility of Rev. Roger J. Smith, pastor of Sacred Heart Catholic Church. Comments can be sent to him by email at firstname.lastname@example.org. To see our many other pages click on the index below.