Quote:Windows 10 version 1903, the next feature update release for Microsoft's Windows 10 operating system, will support the AVIF format.

AVIF, or AV1 Image File Format, is a new image format based on AV1; it uses HEIF as the container and AV1 frames.

Microsoft introduced support for AV1 video in Windows 10 version 1809; administrators had to install the AV1 Video Extension to add support for Av1 video to Windows 10 devices.  The extension is still listed as beta at the time of writing.

While video support is added to Windows 10 version 1809 or later when the codec is installed, support for the AVIF file format is not available in the October 2018 Update. Files cannot be opened in Microsoft Paint or other Microsoft programs, and File Explorer does not display thumbnails if a thumbnail view mode is selected.

Recent Insider Builds of Windows 10 version 1903 offer enhanced support for AV1. Users who store AVIF images on the device will notice that these display as thumbnails in File Explorer, provided that the AV1 Video Extension is installed on the Insider PC.

The images can be loaded into Microsoft Paint as it supports the new image format as well in Windows 10 version 1903.

Full reading: https://www.ghacks.net/2018/12/28/windows-10-1903-to-support-avif-format/