I'd suggest Safebooru. Has great images, and none of the ten-a-penny images I've seen in a hundred different RPs that always end up falling into the same character type.

[url=http://safebooru.org/index.php?page=post&s=list&tags=red_hair+blue_eyes+gun]This search[/url] seems to fit the criteria you're looking for judging by the image you had, so you could probably use that as a starting point?