How graphics contribute to the usability, ethos, or persuasiveness of a document

Using the language and concepts of this lesson’s reading, compose a substantive discussion post that addresses ONE of the prompts below:

How can graphics contribute to the usability, ethos, or persuasiveness of a document?
How might graphics amplify or reinforce the message or purpose of a document? How might they undermine the message or purpose?
What are some of the things we need to be careful about when employing graphics?