Try Screenshot. It comes with more advanced option than the Print Screen button. You can find it by searching "Screenshot" in the Dash.
Another more detailed Screenshot tool
It has a plugin support and some image filters
Install it by ppa
You can add a PPA to your system with the following procedure.
Open a terminal and enter:
sudo add-apt-repository ppa:shutter/ppa
Now, as a one-off, you should tell your system to pull down the latest list of software from each archive it knows about, including the PPA you just added:
sudo apt-get update
sudo apt-get install shutter