For the Shroud, the image is not a photograph in that it is not a product of light. What it most resembles is a topographical map with the darker areas of the image directly proportionally to the closer distances of the cloth from the body. However we can see that the man on the shroud was beaten beyond recognition... the bodily wounds from the scourging could alone have killed him from shock. His face was swollen and covered with blood. Anyone who knew him in his unbeaten form would have difficulty recognizing him after the beating.
It is my considered viewpoint that the Manoppello image is not that of Christ so has no bearing on how He looked on his way to the Cross.