File:William George de Burgh (1939).jpg

Summary
Philosopher William de Burgh (1866–1943) photographed by Walter Stoneman (1876 – 1958), taken in 1939.

Significantly cropped version of CC BY-NC-ND 3.0 DEED version released by (c) National Portrait Gallery. Commerical value resides in selling prints and commerical rights for higher resolution/larger versions. Including a cropped version of an image (for the purposes of identfiying a historical figure at the top of his Wikipedia entry, one use only) that they allow to be freely used (uncropped) for non-commercial projects will not damage those commercial interests. No usable and assuredly public domain alternative has been found despite looking. Subject long deceased, as is photographer. (Reduced to 75% of already cropped version, minimal use.)

immediate source: https://www.npg.org.uk/collections/search/use-this-image/?mkey=mw203898

as per above:

CC BY-NC-ND 3.0 DEED https://creativecommons.org/licenses/by-nc-nd/3.0/