TweetWithSS is a free Chrome add-on developed by arus that allows users to easily take screenshots of YouTube videos and share them on Twitter.

Upon installation, users can click on the icon located in the top right corner of the screen and log in to their Twitter account. Once logged in, a new button will appear next to the captions button when watching YouTube videos. Clicking on this button will capture a screenshot of the video at that moment.

After the screenshot is taken, a tweet window will automatically open, allowing users to easily share the screenshot on Twitter.

Please note that users can customize whether or not the screenshots are downloaded to their PC by right-clicking on the Chrome icon in the top right corner, selecting "Options," and adjusting the settings accordingly.

Overall, TweetWithSS is a convenient and user-friendly add-on for Chrome users who frequently share screenshots from YouTube videos on Twitter.