I am using Emacs for file management.  This involves viewing images
either in a buffer or using `image-dired`.  All worked fine for years.
However recently:

  * There a new image formats, such as AVIF, that don’t diplay out of
    the box.

  * I bought a Sony ZV-1 digital camera, and its ARW raw images don’t
    display.  I already have an idea how to solve that, not too
    important now.

Yes, those AVIF images, why don’t they display automatically?

They are supported by the latest ImageMagick and GraphicsMagick, as
tested on my up-to-date Arch Linux system.  As example, I use:

[hato.profile0.8bpc.yuv420.no-cdef.avif][1]

My Emacs config for testing is attached.  A few minutes ago, I could
open the AVIF file, and it was displayed in `fundamental-mode`.  I had
to manually do M-x `image-mode`.  Then it displayed.  Currently that
doesn’t work at all anymore.  I am greeted by: “Unknown image type”

There are two more things that are confusing me:

  * `auto-image-file-mode` by default is `nil`, but still JPEG images,
    for example, do display.  So I don’t feel like turning it on, and it
    doesn’t seem to make a difference anyhow.  Perhaps it’s a legacy
    option.

  * In the customization buffer, for “Image Converter” it says
    “graphicsmagick” and “CHANGED outside Customize.”  Note that I start
    Emacs as `emacs -q -l init.el` with the attached init
    file.  Certainly `image-converter` is not set there.

I am using: GNU Emacs 28.2 (build 1, x86_64-pc-linux-gnu, GTK+ Version
3.24.36, cairo version 1.17.6) of 2023-01-03

[1]: https://aomediacodec.github.io/av1-avif/testFiles/Link-U/hato.profile0.8bpc.yuv420.no-cdef.avif