How does Gore Vidal use imagery in Lincoln: A Novel?

Imagery:

The cleanshaven face of the poster was hard, even harsh-looking, while the bearded face looked weary, but amiable. To Washburne, the President-elect resembled a prosperous, down-state Illinois farmer come to market.

Washburne carefully stacked the slices of pork to one side of his plate so as to diminish the effect of what otherwise might have looked to be uncontrolled greed.