Cool, I was just looking for something like this. A useful feature would be the possibility to screenshot a specific element only instead of the whole page (using something like https://github.com/GoogleChrome/puppeteer/blob/master/docs/a... ). Also an option to set the ouput filename is a must for scripting !
screenshoteer --url https://news.ycombinator.com/item?id=18598672 --el ".fatitem"