Oh, so I take it she had a history of doing that? That's too bad.
I agree, I thought those poses were generic enough to be no big deal. Maybe it's more the body shape than the pose that was the issue.
I sometimes think that it's too easy to assume something is plagiarized when in fact it really isn't. I had one professor who insisted that I had plagiarized a paper I had turned in, when I absolutely had not, because he didn't think a student could write a paper that well. This was in the days before the internet, and I had written that paper without consulting anyone or any books. (Other than the book we were writing the paper about. It was a Jane Austen novel, and one of my favorites, so I knew it very well.) He didn't flunk me, but he gave me a D, which seriously affected my grade in that class. I'm still angry about it to this day.
So, I tend to take a slightly different view towards accusations of plagiarism, just because I've been innocent and on the accused end before.
On the other hand, I once saw someone post a fanfic that was word for word from a romance novel I had read years ago, with just the names changed. Now, THAT is plagiarism, no question about it.
Artwork, though, seems to me to be a lot harder to tell. Then again, I am absolutely not artistic at all, so maybe I'm not a good judge. 