From our division leader.
If you do not have a license for your artwork, say from Disney-Lucasfilm, where you have been commissioned as an artist, you cannot enforce copyright or attribution of your work on other users on Tumblr, Facebook, Twitter or any platform.
Otherwise, you are restricting my freedom of speech and illegal search and seizure as justified by the United States Constitution and Bill of Rights.
I can sue you for defamation, practicing law enforcement without a municipality of a sovereign government organization, and for breaking cyber statutes under the recent laws.
All the pages and users my pages represent fall under that protection of fundamental rights. You have no copyright if you have no license.
This is my direct statement after consultation with my IP lawyers as a minority business woman and owner.
End of discussion.