Comment # 6 on bug 1053325 from Manuel Stol

Maybe the GNOME images are cached by KDE/Plasma.

Can you clear your icon and thumbnail cache
and see if it helps?

# Clean icon cache
rm -- "${XDG_CACHE_HOME:-"$HOME/.cache"}/icon-cache.kcache"
# Clean thumbnail cache
find "${XDG_CACHE_HOME:-"$HOME/.cache"}/thumbnails/" -type f -delete