Honestly I'm REALLY surprised this picture hasn't gotten more attention because this is BRILLIANT!
Ginny looks less like a Hogwarts witch and more like a superheroine like this, possibly in the mold of Zatanna with a mix of Jean Grey with her in the foreground like this. Smiling and posing, looking cute and hot at the same time. It's a really attractive picture of Ginny without veering into pin-up style sexy fanart you see a lot on this site.
If Harry Potter had a superhero comic we'd seeing Ginny on the cover in a pose like this. I also like the original attire for her. Gryffindor colors with a superheroic motif in it's style, from the shoes on up. That's where the Jean Grey inspiration came in, I can tell.
My only complaint is in the detail of the grass in the foreground. I think you were trying to give it flatland kind of look and not make it so tall but I honestly think you could've given it more detail but that's just a mere nitpick because this is great!