Research at London’s Institute of Physics revealed the image on the back of the famous cloth.
Some believed the 4.2m-long linen sheet was the cloth in which Jesus was wrapped after he was taken down from the cross.
Others dismissed it as an elaborate hoax.
The back of the shroud lay hidden beneath a piece of cloth sewn on by nuns in 1534, after it was damaged by fire.
But the reverse side was exposed during a restoration project in 2002.
Professor Giulio Fanti, of Italy’s Padua University, thought he saw a faint image in pictures from this project and decided to investigate.
Controversy has surrounded the cloth since it was first photographed more than 100 years ago.
Carbon-dating tests in 1979 and 1988 suggested the shroud was a fake.
But, in 1997, a Swiss archaeologist who studied the shroud for 16 years, said new tests proved its authenticity “beyond all reasonable doubt”.