One problem I\'ve been toying with off and on is a service that requires my server to produce a screenshot of a webpage at a given url. The problem is that I don\'t have any
virtual framebuffer X server
I would rather recommend XVFB (virtual framebuffer X server) is the best solution for taking screenshots of a headless server. Virtual framebuffer X server xvfb provides an X server that can run on machines with no display hardware and no physical input devices. I am using that on my server for testing URLs and taking its screenshot. We are using Ubuntu & XVFB + FIREFOX. It is working fine. Modify according to your needs.Take a look on these articles. It might be use full for you.
http://www.semicomplete.com/blog/geekery/xvfb-firefox.html
http://linux.about.com/cs/linux101/g/xvfb.htm
http://www.xfree86.org/4.0.1/Xvfb.1.html