Yes as a parent you have every right to tell them you do not want them using your child's picture.
No you don't.
Usually people charge $10 an hour but some families charge more. Some families that I babysit give me $10 an hour and some give me whatever and it comes to more then $10 an hour. You can always tell the family what you want to charge and they will either... more
Just tell the family that you don't think this is a good fit for you and that you are sorry.
Usually the rate per hour is $10 but some families may pay more depending on if they like their sitter
You dont't tell them you let the school or daycare tell the parents
depending on often you got paid. If you got paid every other week then you should wait 2 weeks and if you got paid every week then you should wait a week.
Just tell them you dont think it's a right fit