Jpeg Images and SSL on Mobile Chrome

Hi There,

This is a real odd one and I only just noticed it so not sure how long the site has been broken.

Take a look at

On your desktop and then on a MOBILE version of chrome. You'll see some images don't load. Look deeper into the site and you'll see more of this.

it seems to be specific to jpg images.
It's not to do with cache or CDN
Images load on staging site which is not SSL.

As you can see no mixed content warning or anything like that.

Everything is set https in WP>General>Settings

Any ideas?