The next version of Windows 10, known today as version 1903 or 19H1, will support the AVIF format. It is a modern image format based on the format video AV1, and developed by the Alliance for Open Media.
AV1 is the latest and greatest of the open video formats. It is designed as a successor to VP9, directly competing with the proprietary (and expensive) HEVC / H.265 codec. It is intended to be combined with the Opus audio codec to create archives WebM for HTML5 web video.
AV1 is currently supported by many industry giants (Amazon, AMD, Apple, Arm, Cisco, Facebook, Google, IBM, Intel, Microsoft, Mozilla, Netflix, Nvidia etc.).
The AVIF image format formats an AV1-based image format. It is already supported by a variety of software, including VLC and Firefox. And from Windows 10 19H1 and on, the AV1 format will be supported from at least File Explorer and Microsoft Paint.
So if you have Windows 10 Build 18305, you can try this new feature in action to see if you can display AVIF images with the paint image editor, of course after installing the AV1 Video extension.