My iphone 4 is linked to someone's ipad?

So i just recently got a iPhone 4 for Christmas, and these children in my neighborhood have iPads from their school, and for some odd reason i'm linked to one of them? I'm not sure how i'm, and everytime they take pictures it goes to my iPhone and i really don't want the pictures on there. Is there some way i can stop this from happening?

You are both using the same account. Get your own Apple ID.