LightShot addon for FF

Exceptionally practical desktop tool allows to screenshot selected area from the screen. Alt+T or PrtSc initiates a screenshot, you select area for screenshot and can perform further actions to Save it (supports *.PNG, *.JPG, *.GIF), upload to server (gives short URL to), edit screenshot online, share link via Twitter, Facebook, Digg. LightShot has easy-to-use interface and very intuitive.

You can also search similar image via Google images search and Tineye!

Other tricks:
Ctrl+C to fast copy to clipboard
Ctrl+S - to Save screenshot to
Ctrl+D - Upload screenshot to server and get short URL on it

Announcements, news, updates, tips and tricks here: http://blog.skillbrains.com
Ctrl+F - Switch to Fullscreen mode
Ctrl+X - exit screenshot mode
Ctrl+mouse hover to select area - will copy screenshot to clipboard right after you will finish selecting