The trouble with the image on the shroud, as the dating attests, is that it doesn't depict what we would expect of a
man of Jesus
ethnic background and time, but rather depicts what we expect him to look like - somewhat emanciapated and long-haired - by the artistic tradition of the "
man of sorrows" that later developed.
However, if we look at the earliest images intended as Jesus in the
Christian catacombs, depicted as the
Good Shepard, then we see a healthy clean shaven young
man with short hair. Whether this was specifically meant to be Jesus or was simply a continuation of repurposed pagan imagery is another question, but at least it attests to the lack of any other tradition at that time. Even if we believe these early depictions to have been deliberately ambiguous as to their
Christian vs Pagan nature, it would seem to highlight that there was no alternate depiction of Jesus that was transmitted to later times.
His image was therefore really a blank slate upon which an iconographic depiction was created based on theology rather than actual appearance.
New Scientist a number of years back published an attempt at reconstructing what a typical
man of that ethnicity/age may have looked like based on modern forensics, depicting him with short hair based on scholarship as to that being the norm, and the result was a more of a rounder faced stocky build, obviously of middle eastern appearance rather than white skinned.
Ben