I'm not sure if this is the right place to post this, so please move this thread if I'm posting in the wrong place.

I'm trying to make a poster for a L&C fanfic I'm working on, but the problem I'm having is I want this character to be blonde. Can anybody use photoshop or a similar program to change the hair of the woman in this picture to blonde?

http://spinoff.comicbookresources.com/wp-content/uploads/2011/07/avengers-black-widow.jpg

I'm pretty sure I can do the rest of the things I want to do for the poster myself, but I just need help with this one detail.