I think the goat reference is total myth. He was called 'The Kid' because, essentially, that's what he was when he killed his first victim at 18 years old.
They are always portrayed in movies as very handsome though, like Clyde in Bonnie & Clyde. He was quite ordinary in real life, but a hunk in the movies !
On the left, Mikey...As often occurs with old photos, especially tintypes, the photo provided with the article accompanying tonyav's at 13.01 is reversed. This is correct: