How does Katherine Anne Porter use imagery in Ship of Fools?

Imagery:

“Steam rose from the river, from the building rooftops, from the mud, from the trees surrounding the town—antediluvian jungle."

Nikos stared out across the bleached sand, the scattered cacti and rock. “Walk with me a while, Bartolomeo.” We walked together across the hot sand, an arm’s length apart. I’d already lost my orientation, and when I looked around, I found I could not locate the entrance I’d used; I was struck by the irrational fear that I might never be able to find my way out of there. Or that Nikos would murder me. My body could remain undiscovered for decades.