Is there any way of taking a screenshot of a website in PHP, then saving it to a file?
I've found this to be the best and easiest tool around: ScreenShotMachine. It's a paid service, but you get 100 free screenshots and you can buy another 2,000 for (about) $20, so it's a pretty good deal. It has a very simple usage, you just use a URL, so I wrote this little script to save a file based on it:
They have a very good documentation here, so you should definitely take a look.