"Gassed". This remarkable picture was actually made in the battle area of France; the men are real soldiers; the cloud in the distance is real poison gas. But the picture was posed, and consequently was "not" approved as "official."
This is an example of the rationale behind American military censorship during the First World War.
Included in - Lieut. Col. Kendall Banning, Signal Reserve Corps, U.S.A., 1926, The Military Censorship of Pictures: Photographs that came under the ban during the World War - and why, (Typescript) www.fas.org/sgp/eprint/photos.pdf