Update:
Short version for Artix Devs: update the following:
from kimageformats 5.109.0-1 in Artix to the version in Arch: kimageformats 5.109.0-2
Artix (unlike Arch) for the second time removed AVIF support.
Affected KDE software:
1. Login Screen (SDDM) = no background, complete white
2. Lock Screen = no background
3. Wallpaper = no wallpaper in KDE
4. Dolphin = no thumbnails
5. Gwenview = KDE Plasma can't display photos
6. DigiKam = broken
7. Showphoto = Editing software (e.g. HDR, Panorama,...) part of DigiKam is broken
....
Artix vs Arch:
Difference:
===> local/kimageformats 5.109.0-1 vs Arch 5.109.0-2
===> local/qt5-imageformats 5.15.10+kde+r9-1 (qt qt5) vs Arch 5.15.10+kde+r9-1
===> local/libavif 1.0.1-1 vs Arch 1.0.1-1
There's a difference between Arches kimageformats compilation and Artix kimageformats compilation: "-1" vs '"-2". Did you miss something again?