What is AVIF
In contrast to the existing proprietary image formats, AV1's image format (AVIF) supports all the standard image codecs and is open-sourced. AVIF images offer significant file size reductions over JPEG, PNG, and WebP images. They are currently compatible with Google Chrome, Firefox, and Android devices. This format is derived from the keyframes of the video format AV1, developed by Alliance for Open Media (AOMedia) in collaboration with Google, Cisco, and Xiph.org. The AVIF image format is already receiving a great deal of praise. Netflix claims it has a superior image quality to compressed file size ratio than JPEG, PNG, and even the newer WebP image formats. Despite JPEG's long history, it is undoubtedly time for a new, advanced alternative, making the AVIF a fascinating development with a high potential for adoption.
What is Quick Look?
Apple Inc has developed a Quick Look feature first introduced in its operating system, Mac OS X 10.5 Leopard. On June 11, 2007, the feature was announced at the Worldwide Developers Conference. Finder users have been able to view the contents of a file at a smaller size in getting Info windows or column views. Still, Quick Look permits users to view the contents of a file at full or near-full size regardless of the document size relative to the screen resolution. Document formats supported include PDFs, HTML, QuickTime readable media, plain text and RTF, iWork documents (Keynote, Pages, and Numbers), Microsoft Office documents (Word, Excel, and PowerPoint) (including OOXML), and RAW camera images. Alternatively, Quick Look can be launched from the command line and opened in full screen. In addition, the slide previews at the side of the preview window can be used to navigate multi-page documents such as PowerPoint slide shows. With Mac OS X 10.5, Quick Look technology is implemented across the entire Apple software suite, including iChat Theater, Time Machine, and the Finder's Cover Flow.
Quick Look supports AVIF with a plugin
Quick Look does not natively support AVIF. It is unknown when Apple will release official support. User dreampiggy on GitHub created an AVIFQuickLook plugin.GitHub Link
You grab the latest AVIFQuickLook.qlgenerator from the Release Page, or build using Xcode. Then open Finder, press Shift + Command + G, input ~/Library/QuickLook/ and press Enter. For macOS Catalina above, use /Library/QuickLook/ instead. Drag AVIFQuickLook.qlgenerator into this folder. You may need to enter the password. After that, you can open any AVIF image with QuickLook.