"Seeing Graner across the courtroom was the only one that was difficult during the trial," he says.
"He had a stone-cold stare of hatred the entire time - he wouldn't take his eyes off me the whole time he sat there. I think this is a grudge he will hold till the day he gets out of prison."
Mr Darby and his family have moved to a new town. They have new jobs. They have done everything but change their identities.
But he does not seem himself as a hero, or a traitor. Just "a soldier who did his job - no more, no less".
"I've never regretted for one second what I did when I was in Iraq, to turn those pictures in," he says.
You can hear Joe Darby being interviewed by Michael Buerk on BBC Radio 4's The Choice on 7 August at 0900 BST.
