How does Frank Norris use imagery in McTeague: A Story of San Francisco?

Imagery:

"There were more than a hundred pieces, and every one of them gold - just that punch-bowl was worth a fortune - thick, fat, red gold."

"This poor crude dentist of Polk Street, stupid, ignorant, vulgar, with his sham education and plebeian tastes...was living through his first romance, his first idyl."