This is the ONLY, absolutely ONLY Screenshot Addon which I have found that really works. I have tried ALL of them, methodically. Many do strange stuff like zooming in and taking screenshot only of the left side of the page, another was taking well the width but not going till the bottom, another was not having the option for full page, etc.
With this you can do ALL, full page, selection, visible part, perfect.
Thanks Manuel :)

Firefox default tool refuses to take lossless screenshot of long pages (.png or lossless copy). Sounds crazy, but it's true - you can read the issue "Ignore the PNG to JPEG Cutoff Limit...". This addon can be used as a workaround. Another workaround is to use developer tools screenshot (devtools.command-button-screenshot.enabled in about:config).

Format string similar to default tool is "Screenshot_%Y-%m-%d %t".

Очень удобно. Ничего лишнего

Really amazing. Capture a scrolling page without the page scrolling before our eyes!
This add-on would be wonderful for Chrome (Skype) too ...

a refreshingly simple screenshot extension which does its job well.

I like how it has no extra bloat, it just efficiently saves a screenshot of the entire webpage or current viewport depending on your needs.

The best part is, it is open source, so you can see how well made it is for yourself! :)

Very good extension!
Author did react very quickly to a reported bug on Github, thanks!

It's perfect. Thanks Manuel.

Best screenshot extensions in the shop. Saves PNG images of full page without compression!

I really like this tool, because it is fast and very easy to understand and use (also for older users, not only for experts). Thank you!

一键全网页截屏 很好

I just tested about 6 or 7 different screenshot extensions — including the big ones like Nimbus, Awesome Screenshot, and Fireshot — and Save Screenshot by Manuel Reimer was the only one that could actually (and COMPLETELY capture and) save the huge webpages I needed to screenshot for archiving purposes. Not only was the capturing process itself much faster the others I have tested in the past, it captured the entirety of the first webpage (in one try) as a 26.5 MB PNG file without any unnecessary loading, superfluous options, or other fluff that normally gets in the way of performing what should be a simple task in a timely manner. It delivered and did everything it promised to do for me as of November 8th, 2018 on my Firefox 62.0 Portable browser — in private browsing mode no less with a VPN on without needing to tweak anything beforehand.

*Funny story about this extension:

I had been so frustrated with the repeated failures of the other webpage capture extensions that, when I didn't see an immediate reaction to hitting the screencapture button, I assumed it wasn't working like all the others and uninstalled it immediately — within seconds because I had my extensions tab open for quick access. To my dismay the "save file as" window popped up almost immediately after I had uninstalled it. I was still able to save the image despite the extension being uninstalled and immediately undid the uninstallation once I realized it had worked. Talk about a close call.

Been looking a long time for a one click-solution that quickly and correctly gets what I want done - thanks!!!

很棒！可以在安卓上使用的长截屏扩展！