I recently switched Binary Moon over to using secure domains. This was quite easy using Cloudflare, however one of the things that didn’t work was making Photon work with https.
Since https implies security Photon disables itself on secure domains (so that no private information can be transferred) – however on Binary Moon I am the only user who logs in, and the images are all public anyway – so I wanted to disable this and serve the resized images over https.
A bit of Googling later and I find a really simple toggle that I added to allow Photon to work on https.
// Allow photon on secure url. add_filter( 'jetpack_photon_reject_https', '__return_false' );
Today I found a separate blog post by Jeremy Herve, one of the Jetpack developers, who goes over this AND how to enable https on WordPress using Cloudflare. To be honest it would have saved me a decent amount of time had I found this first! 🙂