This image is a faithful reproduction of a two-dimensional work of art and thus not copyrightable in itself in the U.S. as per Bridgeman Art Library v. Corel Corp.; the same is also true in many other countries, including Germany.
The original two-dimensional work shown in this image is free content because:
This image is in the public domain in the United States. In most cases, this means that its first publication was in the United States prior to January 1, 1923 or that its copyright expired in the United States.
This image might not be in the public domain outside of the United States (this especially applies in Canada, China (not Macao or Taiwan), Germany or Switzerland). The creator and year of publication are essential information and must be provided. See Wikipedia:Public domain and Wikipedia:Copyrights for more details.
Therefore, this reproduction is also subject to the same terms as the original work.