Think about the styles of Romanticism and Realism. Discuss their differences by talking about two paintings, one from each school, your examples could be from the United States or Europe. Things to consider would be the role of the politics, patronage, revolutions and the emergence of scientific knowledge.
***You could bring in the invention of photography, when was photography invented? How? Discuss some of the major characteristics of Daguerreotype and Calotype photography and their relations to Realism. Or the relation of genre painting to Romanticism or Realism.