In "Armies" Neil has long hair (I think it said until his chin) so how do you picture him? Like, photos?
Ah… okay, I think I answered this one before and might have linked to things. Keep in mind these images are not my own.
Here’s an idea of what he looks like after he gets his hair cut and dyed back to his original auburn color (only a bit wavier than what’s pictured here):
Bangs cut shorter around the face, hair generally chin length (though I can’t find any images with an under cut).
Before the hair cut/return to his original color? Yes, it’s longer, around shoulder length (at least at the start of the fic and he’s bad about cutting it when he’s busy), and black. So he often pulls it back to keep it out of the way, which is why family/friends gives him nice hair ties as presents. :) So like this, only dyed black.