Here's part of a note we found about him in an online article (which may no longer be online) by art historian Gwen Yarker at the Maritime Art Greenwich website —
In the spring of 1918 he [Everett] was commissioned by the Ministry of Information to complete some drawings and paintings of wartime London docks and the Thames which were subsequently exhibited in America…In his paintings Everett also explored the visual effects of dazzle painting. This was a form of camouflage put on ships during the war. He experimented with the formal possibilities these designs offered…
There's another online article by the same author on the relationship between Everett's family and the novelist Thomas Hardy, who was also a native of Dorset. Reproduced above is a reconstructed facsimile (reasonably accurate) of a poster from 1918, announcing an exhibition of Everett's paintings of camouflaged ships.