Jetpack: Photon: Photon links for images inserted in editor when Site Accelerator is active

[KokkieH]

Steps to reproduce the issue

1. With Site Accelerator disabled, create a new post and upload an image via the image block
2. Switch to the HTML editor - note the src attribute of the image indicates the WordPress media file URL.
3. With Site Accelerator enabled, create a new post and upload an image via the image block
4. Switch to the HTML editor and note the src attribute

What I expected

For the image added while Site Accelerator was active to also show the WordPress media URL.

What happened instead

The image shows the Photon URL in the editor (as opposed to being generated dynamically on the front end when the site loads.

After disabling Site Accelerator/disconnecting Jetpack completely, the src attribute for the image when viewing the post in a browser still shows the Photon URL, rather than the media file URL.

Screenshots
HTML view of images added with Site Accelerator enabled and disabled respectively:

Browser inspector showing HTML for image with Jetpack completely disabled on the site:

Reported in https://wordpress.org/support/topic/photon-inserting-https-i0-wp-com-images-in-post-content/

[jeherve]

See https://github.com/Automattic/jetpack/issues/10580#issuecomment-637663083 for a potential way around this.

[hubertnguyen]

I noticed this with the new image comparison plugin as well, just a FYI. It probably goes through the same code path .

[jeherve]

cc @kraftbj Do you think you could take a look at this this week, if you have the bandwidth?

Thank you!

[kraftbj]

I can't duplicate this behavior on either with trunk Jetpack with WP 5.4.2 or 5.4.2+Gutenberg 8.3.0. Asking for others to try to reproduce.

[kraftbj]

Still working on exactly the repo steps. Images of a certain size will trigger it, but not others.

[hubertnguyen]

@kraftbj , I saw your message on Wordpress org. Looks like you're onto it. Let me know you need me to try something. I often use 1000-1500px wide images.
Perhaps the issue happens with "large" but not "full" images?