(I wanted to add this comment next to one of the screenshots, but couldn't see how. Just note that this comment doesn't specifically apply to this line.)
This article is well written and the screenshots add a lot. However, I try to avoid screenshots unless they actually add something that helps the reader, such as navigating around a confusing user interface. If all the reader has to do is type something into a dialog, I would suggest to leave out the screenshot. Especially when the reader is very computer-literate.
I also have a number of minor edits I would like to make to this topic but I don't want to overload you with comments for each line. Should I wait until the pull request is committed?