War is hell! And one of the most disastrous wars, in terms of the painting, would have to have been the impetuous little soiree that Louis Napoleon of France staged against the Prussians in 1870. If the contest had been based upon fashion, the French would have no doubt won. But the bloated pretensions of the so-called Second Empire were no match for the hardened Prussian fighters who destroyed the French army at Sedant, took Napoleon III prisoner, and besieged Paris. Reduced to eating cats and dogs, the art community suffered along with the rest of the citizenry before Paris surrendered in 1871.
Impressionism was in it's infancy at the time. Among the Impressionists, Sisely, Monet, and Pissarro wisely sat out the war in England. Auguste Renoir, who had never ridden a horse, joined the cavalry, and was saved for posterity by getting dysentery. Cezanne hid in the South and painted. Berthe Morisot stayed in Paris, as did Eduoard Manet, who joined the artillery. Only Frederick Bazille, who joined the colorful Zouave cavalry, was killed. He was 29.
Although safe in England, Pissarro's home outside Paris was occupied by the Prussians who used it as an abatoir (a slaughterhouse). They used the canvases they found there as doormats to protect their boots from the blood and the mud. An uncounted number of Monets and over a thousand Pissarros were destroyed this way.