Ignoring the gun, the character on the poster looks innocent. I think she looks innocent because she's small and timid and she's hot with long hair and her facial expression looks as if she doesn't want to be holding the gun and she looks stressed. 

However, when holding the gun, the character looks like an assassin and she's holding the gun as if she knows how to use it and the way she's resting her head on the gun gives me the impression that she's used this gun on several occasions and if anything she's feeling stressed from it. Although the character is holding a gun, the stressed and worried look on her face makes me think that she doesn't really want to be using it and it's more a fact of having to use it.

The fact that it's a small gun signifies that she's quite feminine rather than it being a huge manly, macho machine gun. Because it's small and looks feminine this could attract a male audience.

The houses in the background of the film poster look run down like slums on the right of the character but to her left the buildings look like New York sky scrapers which suggests that she's from a poor place in Columbia such as slums and has found herself New York and as far as we can tell from the poster she seems to be using weapons and killing.