If you ever need to grab a whole web page as an image (ideal for demoing mocked up designs with content both above and below the fold) you could much worse than Nirsoft's website screen shot tool here:

http://www.nirsoft.net/utils/web_site_screenshot.html

It's simple and does what it says on the tin :-) (whilst you're on there, nirsoft's other utils are some of the best out there!)