This is the painting of Napoleon that I was able to see at the Louvre over Christmas time (Paris), by Delaroche, painted in 1848. It is of Napoleon crossing the Alps in May 1800 (before the time of War & Peace). Napoleon commissioned painter Jacques-Louis David to paint him crossing the Alps in 1801, but that painting was "heroic" (not realistic), because Napoleon crossed 2 days after his men on a mule, not on a beautiful horse. The painting by Delaroche (pictured) was more realistic; painted in 1848.
From Wikepedia: "Arthur George, 3rd Earl of Onslow, who had a large Napoleonic collection, was visiting the Louvre with Paul Delaroche in 1848 and commented on the implausibility and theatricality of David's painting. He commissioned Delaroche to produce a more accurate version which featured Napoleon on a mule. While Delarouche's painting is more realistic than the symbolic heroic representation of David, it was not meant to be demeaning - Delaroche admired Bonaparte and thought that the achievement was not diminished by depicting it in a realistic fashion."
