The Windows 10 team is still add some new features to test builds in preparation for its bi-annual Update release cycle for the 2019 calendar year.

A new feature for File Explorer and Microsoft Paint is support for AVIF* format. This old school paint – not Paint 3D, the O.G. The addition to Windows file system support allows users to view, arrange and organize this modern video format.

AVIF support has been seeded to Insiders in several 19H1. While this addtion, whcih many in the video editing world should be happy to see was not  push to our attention by Microsoft but by GitHub developer named AOMediaCodec. He said the follow on the code storeage service about it

Windows File Explorer can show AVIF thumbnails, display Exif metadata and preview AVIF images. Requires the Windows 10 “19h1” preview release, which can be obtained from the Windows Insider program, and the AV1 Video Extension.
MSPaint.exe. The “Paint” app in Windows 10 can display AVIF images. Requires Windows 10 “19h1” preview release build 18305 or later, which can be obtained from the Windows Insider program, and the AV1 Video Extension.

Insiders may need to enable the support, including a download and install of the AV1 Video Extension beta from the Microsoft Store before they can test using it on build 19H1.

* AV1 Image File Format (AVIF) is an open, royalty-free and interoperable solutios for the next generation of media delivery from The Alliance for Open Media.