[whatwg] responsive images

Hi all!

I've read this article
http://www.alistapart.com/articles/responsive-images-and-web-standards-at-the-turning-point

And I've got a suggestion to this problem.

why don't we keep the current markup and use progressive images. this way
the browser could decide what resolution he needs, and when to stop
downloading. this would solve the problem
-having different dpi-s,
-having different size of images.
-on the server the overall disk space needed would be smaller.
-information downloaded by browser could be used to display bigger images
later.
-browser could automatically switch to 'low-res' mode when having poor /
expensive internet connection.

http://www.libpng.org/pub/png/book/chapter01.html#png.ch01.div.2.3
http://www.libpng.org/pub/png/book/chapter08.html#png.ch08.div.6

this problem should not be solved by html markup, i believe.

best regards,
Gabor