1909. The site lists 1909 as the date of creation, and because it is a poster, it was meant to be "published", that is to be printed en masse and displayed. Therefore this comfortably meets PDUS requirements.
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. Note: This tag should not be used for sound recordings.PD-1923Public domain in the United States//commons.wikimedia.org/wiki/File:Society_of_Western_Artists_Poster.jpg
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== Summary == {{Information |Description = Poster for a 1909 exhibit by the [[Society of Western Artists]]. Color Lithograph, 22 1/2 x 14 1/4 in. In the collection of the [[Indianapolis Museum of Art]] |Source = [http://www.imamuseum.org/explore/artwork/7
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