English: 1948, per copyright notice. Note that the film itself premiered in 1947 but was not in wide release until the following year.

English: Scan via Heritage Auctions. Cropped from the original image.

English: The poster included a valid copyright notice, seen at bottom left. However, the copyright for the artwork was not renewed, as was required by American copyright law to extend/maintain protection for works published 1963 or earlier. In order to maintain copyright protection, the poster would have had to be renewed 28 years after publication, in either 1975 or 1976 (see the sections for "Artwork: Original registrations and renewals" and refer to the links to search the copyright catalogs for those years). Because it was not renewed, copyright lapsed at that time. Note that the poster art is a distinct work from the film it represents and had to be renewed separately.