Using WebKit, it is quite trivial to create a tool that grabs the contents of a web page and then saves everything as an image. Together with the new full page zoom feature, we can have the zoomed in or zoomed out version of the page, even at different viewport sizes (which may simulate different screen resolutions). In fact, that is what I describe in Qt Labs on the topic of Capturing web pages.
Just imagine you can have that small utility and you can run something like (web address, zoom factor in percent, output filename, optionally also the viewport width):
webcapture www.trolltech.com 50 trolltech.png
what would you do then?