I have learned that this is indeed the case; the girl was wearing a red facial mask, and somebody (the school knows who) modified the image and changed the color to black. They (two of them) also added racist comments.The girl who had her face "painted" came out yesterday and said this was not a black face joke but a mud mask facial she did last summer. Her friend had pictures on her phone of them and her friend is the one who posted it with the black face comment which stared the whole thing. Kids are organizing protest and fights for today on social media for something which never even happened.
I would look for new friends.
This girl's life has been ruined. She was doxed, and she and her family received death threats. Another example of the old INGO adage "the demand for racism far exceeds the supply".
I don't know how long this has been known, but I am now holding my breath for the media storm of outrage (and retraction).