After days of political tumult in Westminster, a single image of calm suddenly emerged on Wednesday evening from the inner sanctum of royal authority: The Queen granting private audience to a genuflecting Theresa May, who has succeeded David Cameron as prime minister of the United Kingdom. Easily dismissed as nothing more than a shiny scrap of pageantry, the photograph of the newly selected leader of the governing Conservative Party and the monarch who invited her to form a new government is, in truth, a fascinating cultural document.