animuson suggests that an image can be inserted into texts with proper formatting, and what he said is right when you're on a computer or using SE Android app.
That isn't essentially right when you browse SE with a mobile browser, for example Google Chrome 59.0.3071.125 on Android 7.
Markdown source (my avatar):
An image doesn't necessarily occupy a full line, ![Humorous][huaji] yes. [huaji]: https://i.stack.imgur.com/26fxJ.gif?s=24&g=1