How to take a screenshot on Ubuntu Touch

I have flashed Ubuntu Touch on my Motorola Razr GSM (umts_spyder), and would like to take screenshots, but I don't know how. Is there a way to do that?

The easy way (tested on BQ Aquaris E4.5 and Nexus 4 (ota9))

Hold volume up and volume down until you hear the picture sound and see the screenshot flash.

Your screenshot is now saved in /home/phablet/Pictures/Screenshots and you can view them using the gallery app.

Using the commandline (should work on every device)

The phablet-screenshot command found in the phablet-tools package can take screenshots from an Ubuntu device attached via USB cable.

phablet-screenshot foo.png
I: Dumping fb0 ...
2656 KB/s (3932160 bytes in 1.445s)
I: Done

On the BQ Aquarius Ubuntu Phone you have to press the volume up and down key simultaneously. The screenshot is than saved in the Pictures folder.

I RTFM an it said to just press the volume key. I did - right in the middle and it stored the screen capture in my photo folder. From the manual:

Taking Screenshots
You can take a screenshot at any time by simply pressing and holding down the
volume key. The screenshot will be automatically saved in the Gallery, in the
“Screenshots” folder. If you are accessing the phone via the computer, go to
Pictures > Screenshots.