Programmatically create image from web-page or a single DIV

You cannot create image from div for sure but yes you can create dynamic images in php using its gd library. Following links will help:

http://php.net/manual/en/function.imagecreate.php

http://phptutorial.info/learn/create_images/

Here is a great way for you to create images on the client side: http://smus.com/screen-capture-for-chrome-os

You can take this and create a web app that will work nicely on webkit (for other browsers - I'll look at JS polyfills).

Did anyone mention html2canvas and/or jsfeedback ?

It create a page screenshot completely in javascript, then you can send to the server via ajax..

Obviously, CSS support lack some things.