Proton Mail lets users preview AVIF image attachments natively, but it doesn't let us inline the image into the message body like we can with JPEG and PNG. How come? Seems simple enough!

So look, AVIF is a modern image container standard universally supported by all modern browsers and operating systems and has been for years. It's not nearly as ubiquitous as JPEG or PNG, but it is significantly more efficient with its compression algorithm. An AVIF image is significantly smaller and better-looking than an equivalent JPEG, and even lossless AVIFs have better compression than PNG. It is an all-around better format.

I would prefer to use AVIF images in my email communications because it's much more efficient with way smaller attachment sizes, looks a whole lot nicer than legacy image formats, and has better features than JPEG and PNG combined while being supported by all modern platforms. I have no reason not to adopt the image format besides technical limitations such as this, where platforms don't allow me to use it the way I want.

Please fix, there is no down side, thanks! :)