• The full image, seen here, includes a stock number, the name of the studio, and the name of the subject - confirming that this was a promotional image.
• Such images were taken by a studio photographer, and then disseminated to the media and the public for the purpose of promoting their contract stars.

Public domain explanation

• If the photograph was copyrighted, under the terms of the 1909 Copyright Act this copyright would have had to be renewed 28 years after publication. A search for copyright renewal records of 1968 ([1], [2]) 1969 ([3], [4]) and 1970 ([5],[6]) reveal no trace that this occurred.
• This was a common occurrence for studio publicity images, as explained by Eve Light Honthaner, in The Complete Film Production Handbook (Focal Press, 2001), p. 211: "Publicity photos (star headshots) have traditionally not been copyrighted. Since they are disseminated to the public, they are generally considered public domain, and therefore clearance by the studio that produced them is not necessary."