Greenshot - A Free and Open Source Screenshot Tool

Greenshot is probably the best screenshot tool you'll find for free. It is an open source and lightweight software for Windows with simple and easy to understand features. You can easily capture partial and complete screenshots within a second. Take screenshots - upload it to your blog, show it to your friends, enjoy!

Read More: Greenshot Official Website
Download Here: Greenshot Download (Windows)

Well if you are a Linux user you need not worry as there is an alternative to the Greeenshot called Shutter. It is same as Greenshot for Windows. Shutter is free, open-source, and licensed under GPL v3.

Read More: Shutter Official Website
Download Here: Shutter Download (Linux)