pluhsauce
I have mixed feelings about Amanda as Cosette. In the previews...it shows her with blonde hair...wtf? Cosette's supposed to have dark brown hair.
...Really? The colour of her hair has little to do with her talents as an actress. Furthermore, despite her hair being brown in the novel, Cosette is frequently portrayed with blonde hair in the staged musical adaptations. I would say that she's blonde in at least 50% of the productions.
You really shouldn't let whether a character is blonde or brunette ruin a movie for you.
And here are two images of Amanda Seyfried's Cosette having pretty dark looking hair:
http://i.dailymail.co.uk/i/pix/2012/10/16/article-2217042-1587519F000005DC-910_634x928.jpg
http://www.indiewire.com/static/dims4/INDIEWIRE/810d2c2/4102462740/thumbnail/680x478/http://d1oi7t5trwfj5d.cloudfront.net/08/6469208b2311e1bcc4123138165f92/file/amanda-seyfried-cosette-first-look-04.jpg
It might all depend on lighting.
Also, don't let the Annie Leibovitz photoshoot photos confuse you. All of the characters look different in those.