How does William Inge use imagery in Picnic?

Imagery:

“I did some Twelfth Step work down there once before. They put alcoholics right in with the crazy people. It’s horrible—these men all twisted and shaking—eyes all foggy and full of pain. Some guy there with his fists clamped together, so he couldn’t kill anyone. There was a young man, just a young man, had scratched his eyes out.”