You can see the James Dean image here.
I didn't see much of James Dean in Jim Hawkins until I read that the animators started with the actor as a starting point to develop the rebel image. I watched the film again but I still can't see THAT much of Jimmy in Jimmy (sorry couldn't resist) but you can really see it in these concept pictures, can't you?
http://dolphy.shadowwalkers.net/TheMovie/CharacterDesign/Jim07.jpg
http://dolphy.shadowwalkers.net/TheMovie/CharacterDesign/Jim05.jpg
http://dolphy.shadowwalkers.net/TheMovie/CharacterDesign/Jim08.jpg
http://dolphy.shadowwalkers.net/TheMovie/CharacterDesign/Jim09.jpg
This is the best one:
http://dolphy.shadowwalkers.net/TheMovie/CharacterDesign/Jim06.jpg
It's like the classic look James Dean gives the camera:
http://www.imdb.com/media/rm2440730624/nm0000015