[pixelesque]

The format supports that technically (the resolution is stored in two uint32_t variables), but libavif however currently seems to have pretty small limits in this area based off attempts a few months ago to try using it for high res photos: I couldn't get it to save images of size 8192 x 5464 (native Canon R5 res). avifEncoderAddImage() just returns a generic error when the size is too big. If I reduced the size of the image a bit, it then worked.

Given I was trying to store high res panoramas of even larger dimensions, I was pretty surprised at the apparent limits, wherever they exist in the callstack.