Convert web page to image

Awesome : http://wkhtmltopdf.org/

wkhtmltopdf and wkhtmltoimage are open source (LGPLv3) command line tools to render HTML into PDF and various image formats using the QT Webkit rendering engine.

Real answers:

http://cutycapt.sourceforge.net/

http://iecapt.sourceforge.net/

http://www.websitescreenshots.com/

http://www.princexml.com/

http://khtml2png.sourceforge.net/

http://linkpeek.com/

https://htmlcsstoimage.com/ (Uses Google Chrome)

https://gofullpage.com/ - Full Page Screen Capture (Chrome extension) - see this superuser answer for more info

(Don't know of one to use Mozilla's renderer, though.)