I like them but ... I just want to put this out there.
It's not really cool to vector over someone's picture, unless you ask permission. I would not be happy at all if someone came along and took one of my pictures without my knowledge or permission, and vectorized it as their own art.
Of course in a way it is your own art, but in a way it is also not. On Flickr, where that photo is from, you can search photos for ones that allow you to create art from them. Look for ones that are not copyright, all rights reserved. You'll want to find one that will allow you to make derivations - check this page for the codes you want to look for http://creativecommons.org/licenses/