The main message of the story " The Outcasts of Poker Flat" would basically be : punishment without justice is as bad as the crime.
Hope this helps. (:
Do you have an example of the "text"? It's difficult to answer a question like this without seeing the text itself.
Main pieces of imagery can be something describing how stuff looks, smells, feels, or what it sounds like. It should create a picture in your head. So whatever helps illustrate the text for you is an example of imagery! Hope this helps!
I always hear that its a building where all the teachers get together so I think its D