First there was the annoying default “Wine Internet Explorer” for opening images. Why? I found the default source, I deleted it and then it was “Firefox”. Why??? I have different image viewers. Linux distributions are starting to behave like MSW.
Delete local associations:
rm ~/.local/share/applications/wine-* rm ~/.local/share/applications/mimeinfo.cache
and delete global mime cache
sudo rm /usr/share/applications/mimeinfo.cache
This should work for a while. You will be asked for a new default.