Forget about pressing the "Print Screen" when taking a picture of your website. Instead, try SnapCasa, a web application that takes a free snapshot and thumbnail of any web page without much delay.
I like how SnapCasa encourages its visitors to try their service. You don't feel pressured to sign up just to know how the website works. Just input the website's URL and SnapCasa gives you a screenshot of the website in four sizes. Here are the thumbnails of this blog when I tried the website's service:
Signing up for an account is free. Once you've signed up, you need to post a special IMG code into your website to link it to SnapCasa so that the screenshots can be updated regularly.
From SnapCasa website:
"Snapshots appear with no delay if they have been captured before. Depending on server load new snapshots may be processed in realtime or are placed in a queue. Snapshots are updated periodically depending on how often the site being captured is updated and the demand for the particular snapshot."