I’m new here as well as using docker/linuxserver.
I’m still confused about the image updates (pull) regarding custom settings I might have put in place.
Let’s say that I changed piwigo’s php.ini file and later I update the image.
Will the changes I did to php-ini be preserved or will they be lost?
This is a bit of a minefield but it’s only a very tiny minefield. For most containers I’ve ever used the config files don’t get overwritten unless there was a bug in the original. Usually when this happens the change log will have a section labelled “breaking changes”. In fact - it’s always a good idea to read the section called “breaking changes” for any upgrades you do. But - to your original point - in 99.99999% of cases it will leave your config files alone.
If it’s in the config folder, it will be preserved. If you exec’ed in and changed something inside the container, it will be lost.