Over at Google they are always trying to make the internet faster, and just generally better for all of us Speed Craving Humanoids. They weren't happy with just customizing the web pages themselves (even though they released many tools for this such as Google Page Speed and even created a new Web Protocol SPDY), they wanted to optimize every aspect of the assets inside the pages too, which includes Images.
Yes, you guessed it. Google is building a new Image format known as WebP. This new format was tested against 1,000,000 random Images from the Internet to get an average of 39% compression ratio, which is quite impressive on unoptimized images.They have released an open source version of this format for us developers to get our hands on and test for ourselves. I'm gonna try it out later next week when I get some time, but if you're into that sort of thing, you should check it out.
Full details over at the Google Code Blog.