Yep picture tag is really useful. I had tested on WPT and found a big image [1] so I assumed you hadn't taken care of this yet. [1] ~500KB image on 3G mobile

Yep picture tag is really useful. I had tested on WPT and found a big image [1] so I assumed you hadn't taken care of this yet. [1] ~500KB image on 3G mobile device and load time of ~15.9s (https://www.webpagetest.org/result/161224_M7_29Q/ https://www.webpagetest.org/result/161224_M7_29Q/)