What is .... WebP?
Scott Hanselman mentioned WebP in a tweet which immediately prompted my question 'what is that?' The normal answer might be 'yet another web related technology or product that Microsoft has just released'. In this instance, as you'll see from the link, it is a new image format for websites care of Google. They are smaller for the same quality so great; but support for them isn't 'there' yet so my advice, which I'm following, would be to make a mental note and keep an eye on to see if they break into the mainstream.
Another link
See also http://www.pcpro.co.uk/news/361588/google-creates-image-format-for-faster-browsing, though I have no plan to pronounce erroneously as 'weppy'!