So, You Want To Screen Capture, Huh?
http://www.htmlgoodies.com/tutorials/web_graphics/article.php/3479891

Burns, Joe
HTML Goodies
2004

Abstract:

Here's a quick tutorial about screen captures, thus the title. If you're not sure what a screen capture is, then think about the pages you've seen lately. Maybe some of them have had specific sections of the desktop or a program made into an image. It was almost as if they captured part of the screen as an image.