No, I mean the uploader can upload any photo and your Terms of Service should specify what constitutes misuse. You are not legally required to have a Terms of Service, and the photos people upload are not published, but it still doesn't hurt to create an agreement.

You can put a "By uploading an image you agree to our Terms of Service and Privacy Policy" text on the website with the links. This is not a legal advice of course, I cannot be sure that this makes your Terms of Service enforceable, but this is how others like Imgur do it.