Ashley, by using Ancestry, you agree to their Terms & Conditions (link at bottom of page) which includes "You may access the Website, use the graphics, information, data, editorial and other Content only for personal or professional family history research, and download Content only as search results relevant to that research." Before April, the T&C also included "Should you contribute content to the site, you understand that it will be seen and used by others under the license described herein", which is a little more easily understood, in my opinion. Given that information, the users are doing nothing wrong as your use of the site allows them to download it. Also, if you were not the photographer (such as the "old family photographs"), you may actually be violating someone's copyrights by uploading the photos yourself. Generally speaking**, most photographs taken before 1923 are 'public domain'. (**Copyright law is complicated and has changed over time so there is no easy rule.)
It is because of the T&C that I choose *not* to upload photos to Ancestry.