Emulsion is a lightweight, fast, and minimalistic image viewer primarily developed by Artúr Kovács. Despite its current testing only on Linux and Windows, Emulation is targeted for Windows, Mac, and Linux. Wayland support is limited, but X is fully supported. Images appear instantly in Emulsion. At a certain scale threshold, it switches from a smooth display to real pixels. Besides typical zooming features, it offers a dark and light interface for better usability.
There was a newly created Github issue in August 2020 asking for AVIF support. It was almost immediately incorporated into the automated build process.