An American cannot converse, but he can discuss, and his talk falls into a dissertation. He speaks to you as if he was addressing a meeting; and if he should chance to become warm in the discussion, he will say 'Gentlemen' to the person with whom he is conversing.
Where you include any images in your essay, thesis or work, you can describe them as figures. You will need to include them in reference. Figures need to be numbered e.g. Figure 1. or Fig.1 or Figs. 1,2,3. and captioned (described), place caption directly under the image. Number all Figures in the order they first appear in the text.