AVIF support

[jacmaes]

After a previous request for Webp support (6 years ago, times flies…) that Horst and Ryan kindly introduced in PW 3.0.132, I'm back with another request for a new image file format, AVIF, which has landed in almost all browsers. I'm actually surprised no one here in the PW community has been asking for AVIF support in ProcessWire as it seems to be provide much more consistent gains in compression and greater relative quality over Webp, and of course over good old JPEG. My experience using it definitely confirms this.

I've been using Cloudinary to serve AVIF images to the browsers that support it, but of course I'd rather not use a third-party service, and use it natively in ProcessWire. Imagemagick supports AVIF if I'm not mistaken. Anyone else is interested?

[jacmaes]

@horst as the image guru here, how feasible is it? I find that the lack of native AVIF support is an increasing performance issue for me. After more time using this new format, the compression gains are really quite amazing, and consistent (versus Webp). PW-powered sites — especially those that use lots of images such as photography / travel sites — could be much leaner and faster. 

[BrendonKoz]

From a cursory search on the feasibility of this request:
AVIF support does appear to be possible, but there would be more checks required to verify the server configuration meets the minimum requirements...

ImageMagick supports AVIF as of v7.0.25 or later.

PHP's GD library - as of PHP version 8.1 - supports AVIF when compiled with AVIF support, and also requires support via the libavif module. The libavif module must be version 0.8.2 or greater.

At this point there might need to be a decision to determine how to handle image processing: Does a PNG get uploaded and processed and converted to both AVIF and WEBP, and then the smallest of the three options is what is served - or does the site admin decide one or the other (despite gains or losses)? Add in any variations and that's a lot of processing just for a single image.