I have the following setup.A server where my webapp is running. A flickr account where collections of photos are stored.What I am trying to achieve is have various visitors to the site verify their identity using facebook in order to determine which collections of photos theycan have access to. Flickr allows you to retrieve the source urls which I intend on doing before serving themto the client. (http://www.flickr.com/services/api/misc.urls.html)My issue has to do with url sharing. I don't want the users to have the ability to share the urls to photos.Is there a way to address this problem?