There are many samples available on the web, including web service-based solutions. For example @ http://www.zubrag.com/scripts/website-thumbnail-generator.php.
I was NOT implying that you use IECapt, it was ONLY an example. There are scripts that use the GD Library to create the snapshots.
As I mentioned in my original response, "There are many samples available on the web, including web service-based solutions." The poster could have found the WebThumb service and others, if he took the time to search. Here, Let me Google that for you @ http://lmgtfy.com/?q=webthumb+php+script