"Screen Capture" is a fork of the original extension "Screen Capture (by Google)" maintained by Adrià Vilanova Martínez (aka @avm99963).
It allows to perform screenshots of the visible part of the page, a specific region or the entire page. Afterward, it also allows to edit the picture and save it.
Unfortunately, the feature to share the screenshot with social networks has been disabled because it wasn't working and I don't have plans to bring it back in the future. If you want to work on this you can submit a pull request at GitHub: https://github.com/avm99963/screen-capture.
Also, pull requests and bugs are welcome at https://github.com/avm99963/screen-capture.