While researching the subject, I have come across two volumes that I thought anyone with an interest in the 1st Empire might be curious about. Both are previously published, but relatively easy to find and inexpensive.
Leslie Humm Cormier, All the Banners Wave: Art and War in the Romantic Age, 1792-1851. Providence RI: Brown University Press, 1982. 124 pps.
The was the catalog for an exhibition held at Brown University depicting works by a variety of French artists including Charlet, Raffet, Bellange, Vernet, etc. The text is excellent, with separate subsections on depictions of the military hero, Bonapartism in art and politics, Raffet and the role of the print, and more.
Albert Boime. Art in the Age of Bonapartism, 1800-1815. Chicago: University of Chicago Press, 1990. 705 pps. This is volume two of professor Boime's (Univ of CA) four volume history of Modern Art. This is social history, however, not a history of art movements, in which the author sinks the reader into a total cultural experience. Art, literature, philosophy, politics, economics - they all get equal footing here. The complex relationship of Napoleon and art are unentangled and Boime looks at contemporaneous French, Spanish, English, German, and Italian artists at work during this era. His description of the creation (and control) of German nationalism is fascinating.