"Usage" in all docs is broken link

Just reinstalling on a new device, and I don't remember how to use, so I went to check the readme.md, the PyPI page, and the githubio page, and they all just link to a screenshot (or just SAY screenshot-help.png), but there is no such screenshot at the location. You may want to have an actual written usage there just to avoid this in the future.

Fortunately, the --help command is well set up :)