How does Vernor Vinge use imagery in A Fire upon the Deep?

Example of Imagery:

"Daylight had faded from the cracks in the walls. Soon the digger teams would be turning in their hoes and marching off to the barracks over the edge of the hill. Across the straits, the towers on Hidden Island would be golden in the mist, like something in a fairy tale., their whitejackets would be calling Amdi and Jefri for supper any minute now."