A vivid description that is used to "paint a picture" in your head about what something or someone looks like. All five senses are being used to form this image.
Examples of Imagery:
Page 39 of Delirium by Lauren Oliver
"I'm at the edge of a big white cliff made out of sand. The ground is unsteady. The ledge I'm standing on is starting to crumble, to flake away and tumble down, down, down—thousands of feet below me, into the ocean, which is whipping and snapping so hard it looks like one gigantic, frothing stew, all whitecaps and surging water."
This example is talking about a the main character's dream, helping you understand the the setting, which is the place where her mother died. The description is helping you understand her feeling towards this place and what happened. It also helps you better connect to the characters situation; loosing someone who you loved, but everyone else believing that your nothing.
Sunrise, Emma Miars
“As I glanced out my window, I could see a sliver of light peaking out from behind the hill, lighting up the sky from a blue so dark, I thought it was a demons soul; to a rainbow, bringing light and love to the dreary night. The night that once was enslaving the clouds, forcing them to lock me up in this broken world, was now over come by day, freeing both me and the clouds to live in peace and escape before the nights soldiers overrule the day. Before they takeover every hope and dream we made while they were away. Like what they did the night before and all the evenings before last night and what they will try to do every night in the future."