Just so you know, on Firefox 92.0b7 the phone images won't load. Apparently the network request works fine, but when trying to view the image directly Firefox says that "The image <...> cannot be displayed because it contains errors.".
Thanks, I couldn't reproduce it with the stable build but I did with 92.0b7. Seems to be related to avif images and a bug in libheif. Trying to fix now.