I know there are plenty of online tools which let's you upload your images there and it generates the appropriate CSS/sprite(s) to be used with them on your page.
Is there any such website/tool which would take a website URL and parse from its DOM the images/css and calculate the sprites/css to be used specifically with that DOM, so you could just copy & replace your own CSS with the one provided by the tool?
I know the complexity of such calculations, but it certainly sounds like something that can be done, so my question is, is there something ready and available already?