Shutter is a feature-rich screenshot program. You can take a screenshot of a specific area, window, your whole screen, or even of a website – apply different effects to it, draw on it to highlight points, and then upload to an image hosting site, all within one window. Shutter is free, open-source, and licensed under GPL v3.
To install Shutter open a terminal window (press Ctrl+Alt+T) and copy+paste the following lines:
sudo add-apt-repository ppa:shutter/ppa
sudo apt-get update
sudo apt-get install shutter
To start Shutter press Alt+F2 and type: shutter
Shutter Homepage