I have no way of contacting this other person and they are currently using up 1.5KB of my storage. I am only able to have a total of 5 apps because of this and my phone will no longer allow me to take any pictures. I tried to back it up to my computer in hopes that I would just be able to make a new Apple ID account but there was no luck with that. When I tried it said that I don't have enough available storage to back it up so now im stuck.
IS this photostream? If so that is based on your AppleID. Change your password. Then go to photostream and click select, now delete photos. IF it is iCloud photo sharing, cclick on edit and the click the X to shut down that share.