No statement of copyright ownership is required by law, and its absence does not weaken the protection of copyright. But it is still a good idea to include one in order to counter someone arguing that they were unable to find out the copyright status of the work or whom to ask about permission. Images whose rights status and ownership cannot be determined are called 'orphan works'. The copyright statement should appear on the same page as the image on the web, on the back of prints, and also in the metadata of all image files uploaded or emailed anywhere.