How does Willa Cather use imagery in The Diamond Mine?

Imagery:

I FIRST became aware that Cressida Garnet was on board when I saw young men with cameras going up to the boat deck. In that exposed spot she was good-naturedly posing for them, amid fluttering lavender scarfs, wearing a most unseaworthy hat, her broad, vigorous face wreathed in smiles.

One of them was her sister, Miss Julia; a woman of fifty with a relaxed, mournful face, an aging skin that browned slowly, like meerschaum, and the unmistakable "look" by which one knew a Garnet. Beside her, pointedly ignoring her, smoking a cigarette while he ran over the passenger-list with supercilious almond eyes, stood a youth in a pink shirt and a green plush hat, holding a French bulldog on the leash. This was Horace, Cressida's only son. He, at any rate, had not the Garnet look. He was rich and ruddy, indolent and insolent, with soft oval cheeks and the blooming complexion of eighteen. He seemed like a ripe fruit grown out of a rich soil; "oriental," his mother called his peculiar lusciousness.