If you have new concepts in your story, or new things, you might be able to cut down on the lines of text dedicated to describing or explaining it by drawing a picture. People tend to take in words differently and so text can be imagined in a number of different ways other than you mean it. This is why additional lines of text would be used to narrow in on the authors intent.
Also, if you want to expose on something related or unrelated to the particular story thread your talking about at the time, you might be able to use the chapter heading, or the classic chapter page, as a place to offer a brief exposition on some facet of your world. People who play video games recognize this as the "loading screen" where they offer you something to read while you wait- a bit of flavor text to further flesh out the ambiance of the world the story takes place in. It can also be used for things like foreshadowing.