Plugin: Media Credit
This plugin extends the functionality of the WordPress media library by adding some key rights management fields to the image editor. After installing the plugin, you'll gain fields dedicated to properly crediting an author and organization, as well as the ability to identify a photo as one that can be distributed in an automated way.
We used the plugin on our project to identify photos that could be redistributed via our API and imagined that other organizations might encounter a similar need. Download, extend and enjoy.