James McNeill Whistler, Trouville (Grey and Green, the Silver Sea), 1865, Oil on canvas, Art Institute of Chicago, Chicago. https://dartabase.art/cite/aic/81572

James McNeill Whistler, Grey and Silver: Chelsea Wharf, c. 1864/1868, oil on canvas, National Gallery of Art, Washington. https://dartabase.art/cite/nga/1238