I tried to make the preview the same (in fact, I didn't want a preview at all), but the image was larger than 100 pixels at it's original size so it was impossible to upload the image without either shrinking it or uploading a different one. And since shrinking it would have ruined it I uploaded the image this one is based on (this image is a detailed version of the image I used for the preview).
As for the flatness, I'm not sure how to fix that. This picture doesn't really look right to me, but that always happens on large images.
I am not sure, still kind of new to here, but I think that preview is supposed to be the exact part of the picture itself, not something completely different as in your case. And the picture .. It has some odd flatness to it, it looks more like a mask.
K *will change it in a sec*