These World War II posters and sketches from Britain's National Archives plunge us directly into their wartime experience, where the outcome was far from certain and daily life was rife with danger and privation. From a collection of 350 artworks newly digitized in high resolution (thanks to a grant from Wikimedia), their purpose was threefold: propaganda, information, and morale boosting. This first group is of the "loose lips sink ships" ilk.
This next grouping shows Princess Elizabeth, Churchill, and a member of the Women's Royal Naval Service (WRNS or "Wrens").
Finally, these posters attempt to influence behavior.
For actual "you are there" photographs of soldiers in various theaters during the war, have a look at The U.S. Army in World War II: The Stories Behind the Photos.