Shutter is a feature-rich screenshot program for Linux based operating systems such as Ubuntu.
Source Shutter Homepage: http://shutter-project.org/
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.
To install Shutter just run the following commands via your systems terminal.
sudo add-apt-repository ppa:shutter/ppa
sudo apt-get update
sudo apt-get install shutter