P S I was not aware of this DR when I wrote the explanation above I ve however found the corresponding OTRS ticket see ticket 2010030110058288 where F forwarded the Flickr mail correspondence with the copyright holder It shows exactly how such exchanges look like when OTRS processes and the requirements of a formal license declaration are not known But most of these cases get caught through tagging or deletion requests like this one In this case the license problem was apparently solved by the copyright holder tagging that image with cc by sa at Flickr