Before I start ranting about all of the impossible ways that people claim should work, here is actual solution:
sudo apt-get install gnome-web-photo
gnome-web-photo http://google.com gnome-web-photo.png
Why was that so difficult, internet? Why so many options that do not work? I blame the google algorithms that place value on the oldest links. The oldest method is seldom the best when technology is concerned.
If the above doesn't work, here is a backup method:
sudo apt-get install wkhtmltopdf imagemagick
wkhtmltopdf www.google.com google.pdf
convert -quality 100 google.pdf google.jpg
Now let's talk about about the stuff that doesn't work.
Does this work on your OS? I just get seg faults.
This hasn't been hip in 4+ years and clearly doesn't run on modern Ubuntu installations.
webkit2png and PyWebShot
Both of these supposedly work great... if you're on a Mac. Why are you on a Mac? I have no idea. Does anyone run a Mac server? No. So what is the point of programatically taking a browser shot on them anyways? Who cares.
Apparently Apple bought some company that owned some code or something that webkit python bindings need or whatever who cares. The short story is that you cannot install pyobjc on Linux because of Nazism because you get some horrible pip error:
ValueError: invalid literal for int() with base 10: ''
So basically, it's looking for your OSX version but can't find it because you aren't stupid enough to be using a Mac. Every day I get more glad Steve Jobs died an untimely death. What a prick.