Just separating two issues.
1. The extent to which we know what Jesus looked like and the source of that knowledge
2. The usefulness of such images even if a faithful reproduction.
1/ On the first - it is important to recognise the origin of iconography.
The iconography became and has remained very consistent from around the time of the mandylion in edessa: a cloth holding an image - ( indeed reproductions include some defects which are also recognisable on the shroud of turin). The probability is that the mandylion was the shroud folded to expose the facial areas, and that iconography was based on seeing it.
Several Recent physiochemical datings of the shroud based on several different physiochemical properties are indeed first century (proving the Radio date was false - as most evidence said it was, even at the time it was done).
And the shroud - and forensic correspondence with the sudarium (which is beyond reasonable doubt) , contain between them the pre and post forensic pathology of a man tortured exactly as the description of Jesus was in the gospels: a case unique in historic record.
Therefore it is entirely reasonable to believe that the common icon is indeed what Jesus looked like and is based on forensic evidence, not hearsay.
There are many papers written on the iconography and correspondence, hunt them - they make interesting reading.
2/ The usefulness.
Clearly there is a very subjective aspect to that.
Visualisation that helps some , does not help others.
Neither choice is exclusively right
It is also interesting that the visions of Jesus by mystics often portay his heart - such as the "sacred heart"
It is interesting to note that there are stained glass reproductions of Christ surviving that are a millenium old. It is only in recent times that the ordinary man could read, so stories were told in glass in churches.
Hey. I am sorry but I have to get this off my chest right now. I can't help but look at those pictures of Jesus on the internet. That is some really bad photos. They have no life in them and I know Jesus has more heart then that. I am starting to think maybe some people don't really know Jesus at all and only worship in vain or only love him the way he is represented in this world. Especially and in those pictures. I dont think many people have come to know Jesus for who he really is. I am sorry but I do not like those photos cause they misrepresent him and when I look at them there's no life in them at all. Wouldn't it have been better just to not make photos of him at all and just go by his teachings? What is the purpose of them pictures though? If nobody know what Jesus really look like, why not just leave at that and not misrepresent him by portraying him in such things as such. Especially those pictures. I know a lot of people say they love Jesus and they are close to him and they probably are but I really do wonder why people sometimes do. why some people worship and love Jesus the way they do? Because we have a person here with a heart (a beautiful one too hehe) and feelings like us. A person being misunderstood and misrepresented in the world causing some to overlook who Jesus really is or could be and that there's probably more to it then one could imagine about him. Causing him to still be mocked ridiculed and despised in the world because some people just don't get it...
