I need some advice..?

[Kyo]

My younger sister came to me for advice for a friend. (I am going to refer to my sister and my sister, the friend that ashed for the advice a miss A, and her friend's friend as miss B)

Miss B made a fake facebook account for Miss A. It had a fake name, but the picture is something that Miss A wasn't fond of. Miss B put the profile picture as a picture of half of Miss A's face, and the rest of the picture was of her cleavage.
I know that some people don't find it that big of a deal, but Miss A is very innocent and replaced the photo right when she saw it, to a picture of her face, not her cleavage.

A few days later she got a group message from a boy from her school who has a grudge against her.
It had the picture of Miss A's cleavage saying "This is actually Miss A" and stated her real name.
The message was to multiple people at her school and now Miss A is worried that her photo will spread around her school.

Neither my sister or I know what to tell Miss A. Miss A is a very close friend to my sister which makes her basically my little sister. My sister didn't tell me the boy's name (because she knows I have somewhat of a quick temper and thinks I will beat him up.) so I can not confront him, or talk to his parents.

I just want to know what I should tell Miss A. Please, if you have any advice for us, comment.
So, when I said Miss B made it for Miss A, I mean Miss B had permission from Miss A, but Miss B did all of the work. And instead of consulting Miss A on the photo, she put up the photo of her cleavage.

I am not entirely sure on why the boy has a problem with Miss A. They didn't tell me his name, all I know is that he has a grudge against her.

[Bala]

First things first. Does Miss B know that building a fake profile with Miss A's information without her permission can be treated as identity theft and she can be prosecuted legally?

Coming to Miss A's problem. Why does the boy hold a grudge against Miss A? Is there some history here? If there is some unresolved history that's causing the problem here. Moreover what this kid is doing can be considered Cyber bullying. I would prefer going to the authorities or his parents with the evidence to dealing with the situation myself.

Last but not least - what Miss A needs to remember is that in today's world, no one has long enough memories to tarnish her reputation in any way. A few months after this is all over, no one would remember that such a photo of her exists. The best way to deal with it would be to ignore the whole situation. The more she tries to deny that it isn't her photo, the more the rumor spreads and stays longer with the people.

Just keep her parents informed of what's happening because she would need a lot of support from family and friends in case it blows up and authorities get involved.