How does Ulysses S. Grant use imagery in Personal Memoirs of U.S. Grant?

Imagery:

"Orders had been given, long before this movement began, to cut down the baggage of officers and men to the lowest point possible. Notwithstanding this I saw scattered along the road from Culpeper to Germania Ford wagonloads of new blankets and overcoats, thrown away by the troops to lighten their knapsacks; an improvidence I had never witnessed before."