How does Graham Greene use imagery in Our Man in Havana?

Imagery:

"The separating years approached them both, like a station down the line, all gain for her and all loss for him."

"He was glad that she [Milly] could still accept fairy stories: a virgin who bore a child, pictures that wept or spoke words of love in the dark. Hawthorne and his kind were equally credulous, but what they swallowed were nightmares, grotesque stories out of science fiction."