The "picture counterpart" of WebM is called WebP, and it gets about 30% savings over jpeg. While you can't serve it to everyone until all browsers support it,

The "picture counterpart" of WebM is called WebP, and it gets about 30% savings over jpeg. While you can't serve it to everyone until all browsers support it, if you'd like to convert images to WebP and serve them only to supporting browsers you could use mod_pagespeed: https://developers.google.com/speed/pagespeed/module https://developers.google.com/speed/pagespeed/module (Disclaimer: I work on mod_pagespeed and ngx_pagespeed at Google.)