Huge flaw in your statement. He was seen multiple times AFTER His death and resurrection. Matthew 28:1-20, Mark 16:1-8, Luke 24:1-12, John 20:1-10, etc.
According to the Bible, once he was taken to the tomb, he wasn't seen until his 'resurrection'. Of note is that those who saw him, saw his 'body' or 'appearance' to be that of JESUS before he was tortured and put on the cross.
If angels can appear to have a human 'form', why couldn't Jesus, after he died, have done the same?
Especially if his original body was 'destroyed' by the 'resurrection'.
I don't think the Bible meant that Jesus was 'resurrected' in the same sense that people bitten by ZOMBIES suddenly stand up and walk away with their 'deceased and damaged' form.
Do you?
Jesus the Christ, later 'rose' into heaven. I don't think the physical body can do such a thing, and that the 'appearance' of Jesus (formed by the 'spirit' or 'soul') was what actually 'rose'.
Most of the insistence by religious experts that Jesus's PHYSICAL BODY rose into heaven is only to explain why his PHYSICAL BODY was not found in the tomb.
I am just proposing an explanation for why it wasn't, and how the 'radiation marks' could have gotten onto the cloth , (or , as another article has pointed out, the image is not on the cloth, but on the SOAPWART.)