Gassed, by John Singer Sargent (large version).
Sargent comments on the difficulty of finding a subject suitable for his commission. From the Imperial War Museum's label for the painting:
The scene is the aftermath of a mustard gas attack on the Western Front in August 1918 as witnessed by the artist. ... Sargent travelled to France with artist, Henry Tonks in July 1918. Tonks describes the context for this work in a letter to Alfred Yockney on 19 March 1920: 'After tea we heard that on the Doullens Road at the Corps dressing station at le Bac-du-sud there were a good many gassed cases, so we went there. The dressing station was situated on the road and consisted of a number of huts and a few tents. Gassed cases kept coming in, lead along in parties of about six just as Sargent has depicted them, by an orderly. They sat or lay down on the grass, there must have been several hundred, evidently suffering a great deal, chiefly I fancy from their eyes which were covered up by a piece of lint... Sargent was very struck by the scene and immediately made a lot of notes.'
Sargent was commissioned by the British Government to contribute the central painting for a Hall of Remembrance for World War One. He was given the theme of 'Anglo-American co-operation' but was unable to find suitable subject matter and chose this scene instead. "The further forward one goes," he wrote "the more scattered and meagre everything is. The nearer to danger, the fewer and more hidden the men -- the more dramatic the situation the more it becomes an empty landscape. The Ministry of Information expects an epic -- and how can one do an epic without masses of men?'
Perhaps the lack of the epic nature is at the heart of Obama's difficulty in finding drone pilots to blow far away brown people to pink mist from the comfort of air-conditioned trailers.