qScreenshot is a free and lightweight tool that allows users to take and edit screenshots under Ubuntu. With this tool, you can capture full screen, specific area on your screen, or current active windows. The screenshots taken can be then edited with the built-in graphics editor. You can also save these screenshots either to your local hard drive or send them to a remote host with the possibility to connect to proxy servers.
Once started, qScreenshot's icon will show up in the system tray (top panel), click it to select an action:
In the Settings window, you can set the application to start automatically at system startup, modify default keyboard shortcut for taking screenshots, add servers, etc.
To install qScreenshot under Ubuntu 11.10/12.04 or older, open the terminal and run these commands:
cd /tmp && wget -O qscreenshot-0.6-1-i386.deb http://goo.gl/xllHG
sudo dpkg -i qscreenshot-0.6-1-i386.deb
If you are running Ubuntu under VirtualBox, you may get blank screenshots with qScreenshot. To fix this, you need to disable the 3D acceleration option in the VM settings window:
The qScreenshot home page can be accessed here.