Resize browser content area?

I am wondering if there is a way to resize a browser window (content area) to precise dimensions. What I want to do is create tutorial articles with browser examples and want the sizes to be uniform across the whole site. I know I can resize images with gimp, photoshop etc but is rather not resize and lose any quality. I realize this is a weird question and not 100% graphic design related but it is about producing HQ images for my site, so if you've ever heard of some kind of browser resized that you can input width/height parameters in pixels that would be great, every google search I tried was giving java scripts to control client browsers and things like that. Shot in the dark I know. Thanks!

I think I vaguely remember that it can be done but I can't remember enough I am afraid.

Try these:
http://www.pcmag.com/article2/0,2817,2339650,00.asp
http://sourceforge.net/projects/winsize2/
http://www.eusing.com/WindowManager/WindowManager.htm