What does it mean when a girl hugs you in front of her friends?

Well, a few weeks ago I was having an average day at school, when this popular girl came up to me calling my name and gave me a hug in front of her friends. I was rather stiff and told her I wasn't feeling so well so she might as well get off me. And then just recently, it was the school's swimming gala and she showed up again and hugged me asking her friends to take a picture of me and her. I was in my swimming pants all wet and soaking. I was so damn embarred! But why is she doing this? If she liked me, she could have done this when none of her friends were around. Or is she just trying piss me off?