Safari iOS 16 started to support the new AVIF image format according to this blog post https://webkit.org/blog/13152/webkit-features-in-safari-16-0/
I tested it with the url https://avif-support-test.glitch.me/ It works well on my iPhone, macOS Ventura but not iOS Simulator 16.2.
It tried to fetch the image resource but got an error "An error occurred trying to load the resource"