It’s easy. Bring up the webpage. On your keyboard hit the prt scr key. Go to accessories, paint and open up paint. Go to edit on the tool bar and hit paste. Save it. That’s it.
Did you notice the Mods just gave you your own thread in breaking?
That works in Linux as well: hit Print Scrn and capture entire screen, then a little window pops up using Ksnapshot asking where to save it or print it. The default name is “snapshot1.png”. Simple and quick!