How does Caroline Dale Snedeker use imagery in Downright Dencey?

Examples of Imagery:

"Dencey knew with an intensity that equaled its vagueness that if she let go of Jetsam, he would tumble back into an abyss."

"Jetsam was lost - utterly lost. All the horrors of hell its fleshly burning and inward soul agony which her grandfather had so aptly described came back to her."