I have many pages on the site. How to make it so that when starting the script, I have a screenshots of all pages available on the site in good quality? Tell me in what direction to move? What to write this script?

UPD: This is the service. http://www.s-shot.ru/-He makes screenshots. But the quality leaves them to desire the best. Tell me, if you write manually and use the function for the screenshot from Windows as written in response below, the quality will be similar or other?