How does Dave Eggers use imagery in Zeitoun?

Imagery:

"Once the sardines were ready, tens of thousands of them glistening in the refracted light, the fisherman would cinch the net and haul them in."

"In minutes the boat was gone into the darkness. He was alone at seat for two days, with sharks below and storms above, clinging to the remnants of the barrel, when he finally washed ashore."