How does the author use imagery in the story, A White Heron?

Example of Imagery:

The woods were already filled with shadows one June evening, just before eight o’clock, though a bright sunset still glimmered faintly among the trunks of the trees.

The cow stopped long at the brook to drink, as if the pasture were not half a swamp, and Sylvia stood still and waited, letting her bare feet cool themselves in the shoal water, while the great twilight moths struck softly against her.