Known problems 

• Screenshots need HTTPS and a browser with screen capture (getDisplayMedia()). Without it the dialog works, but without a screenshot.
• The extension is tested in Chrome. Firefox and Safari are not tested yet.
• Drawing markings on the screenshot needs a pointer (mouse, pen or touch); all other controls work with the keyboard.
• Images on the page and the document size are only part of the admin panel details when the page was rendered without cache.

Report problems on GitHub.