Photon

Featured Image is not processing by WordPress CDN ( Jetpack Photon )

The images in the post are served by WordPress CDN(i.e. Jetpack Photon) but featured image is not. You can check any blog post from my website. Here is an example post: http://www.rswebsols.com/tutorials/ecommerce-tutorials/infinite-scrolling-kill-ecommerce How can I achieve this?