English: Production still for the film The Wild Bunch. Director Sam Peckinpah on right.
The photograph was taken on-set by the studio, most likely for publicity purposes. Such images were then disseminated to the media and the public to promote the film (see Film still).
It is definitely not a screenshot as an exact image like this never appears in the film.
Since the image was published prior to 1977, under the terms of the 1909 Copyright Act (which was law until 1978), any copyright that may have been secured for the photograph would have had to be renewed 28 years after publication.
The copyright for this image would therefore have had to be renewed in 1996. A search with The United States Copyright Office for "The Wild Bunch" finds no trace that this occurred.
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.