It would be hard to know, especially older paintings, what the mindset of the artist was. It would be hard to know what film makers have as their attitude without asking them. Some of what we call “Masterpieces” portray Jesus with long hair and perhaps Hollywood influenced by such paintings just create their image of Jesus from that. If the Bible does not tell me about the color of His hair then it would stand to reason I do not know about the length of His hair. I may not know the length of His hair as to inches but something else needs to be brought in at this point.
All the statues of the Romans during this period of time have men with close cut hair. The Bible is from God and therefore there is no contradiction. Paul in writing about the culture of the first century world declared that it was a shame for a man to have long hair (I Cor. 11:14). The word he uses in this verse is the word, “nature”. Nature does not mean what man is born with but that which is a result of continual practice. We sometimes say about some athlete that he can shoot a basketball without thinking. He has practiced it so much that it becomes second nature with him. The idea expressed by Paul was that the idea of a man with long hair was viewed as a shame.
Under the Old Testament if a man chose to be a Nazarite he did not cut his hair while under that vow. The vow was often taken for a short period of time and the hair would be cut at the end of the vow. Samson was a Nazarite from birth to death (Judges 16:17). However, when his hair was cut it referred to the seven locks of hair (verse 19). More a reference to the thickness of hair instead of the length. As a Christian both in hair or dress code, I would not want to convey to the world that I am anything but a righteous man. If the length of my hair conveys a different message then I need to get to the barbershop as quick as possible.