I recently discovered that a specific Ancestry.com user has downloaded a large amount of photos that I have submitted to my tree, and resubmitted them under his own username without making any changes or edits to the photos. I also noticed that this user had done the same thing to pictures submitted by other contributors. It's very frustrating, as they represent a lot of work on my part. Is there anyway to prevent this, other than making my family trees private? Thank you!