This applies to the European Union and those countries with a copyright term of 70 years after the work was made available to the public and the author never disclosed their identity.Important: Always mention where the image comes from, as far as possible, and make sure the author never claimed authorship.
Public domain works must be out of copyright in both the United States and in the source country of the work in order to be hosted on the Commons. If the work is not a U.S. work, the file must have an additional copyright tag indicating the copyright status in the source country.