There is an excellent expression on this girl's face. For the challenge, it is a bit difficult though.
I like this image a lot better for the challenge when I crop to exclude the green background. I'm not so sure when taken on it's own context though.
I find the contrasting purple in her shirt and green in the background to be highly distracting. When removed, the attention moves right back where it belongs - in her face. I also removed a slice from the top to counteract and keep the eyes on the top third.
I _almost_ really really like this image, but something about it doesn't quite sit right with me. I wish I could explain it for you... maybe upon re-visiting it I'll be able to.
(Hmm, actually... her face almost seems posterized to me, maybe that's it. And over her right eyebrow (the one to the viewer's left), there's a lightness which I find distracting.)
Une belle fille. C'est une honte que vous avez dû overexpose votre image pour obtenir votre blanc de fond. Vous avez perdu trop de détail sur votre sujet, son bras et le nez sont allés. Peut-être si vous aviez employé réellement un fond blanc, au lieu de forcer un, c'aurait été une meilleure photo. (traduction par des Babel Fish)
I love this. If only you could have gotten that green out of the background it would have been a perfect submission for the challenge, still a great photo though.