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Under Linux to try a variety of tools, integrated down, think shutter is the best use, recommend everyone to use.

Shutter is a powerful tool that integrates powerful features into an intuitive, simple interface, with applications that come with multiple areas (such as fullscreen, select Interface, active window, website, etc.), convenient application features, and the ability to have numerous plugins and uploads to Web services.

Install shutter:

sudo add-apt-repository ppa:shutter/ppasudo apt-get  updatesudo apt-get Install Shutter

If you want to make the tool like QQ, with the keyboard shortcut to recall, you can refer to the following steps.

1. Find Keyboard settings

2, custom shortcut keys

3. Set shortcut keys

Shortcut keys inside the command by:shutter-s or shutter--select

• Retrieving the current window: Shutter-a (A for active), Picpick is using (alt)+(prtscn), the ALT key is not available in Ubuntu, so instead (win)+(prtscn) (shown as Super-print).
• Fetch drag Area: Shutter-s (S is the meaning of select), drag out the rectangular area and press ENTER; I use (shift)+(prtscn) (shown as Shift-print).

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