http://www.nextmovie.com/wp-content/uploads/2013/07/Van-Ronk.jpg

The photo you're talking about might have been a nod to Freewheeling Bob Dylan but, If anything that's just an example of how idiosyncratic Llewyn is, instead of a pretty girl on his arm, he has a cat. So you could say they is a parallel to Dylan in that case but everyone involved has said the movie is more or less a kind of inspired by Van Ronk.

I just think the main point is that you shouldn't go into the film expecting it to be an alternate universe Dylan.