Za one koji imaju dosta slika na sajtu evo rešenja iz guglove laboratorije.
“WebP is a method of lossy compression that can be used on photographic images. The degree of compression is adjustable so a user can choose the trade-off between file size and image quality.”
http://code.google.com/speed/webp/
http://googlecode.blogspot.com/2010/09/webp-new-image-format-for-web.html