Hello
I have installed the language file for the simple image gallery version 2.5.0. which is rather old 18. Sep. 2013

I cannot uninstall this language file via the backend:
Error message:
This language cannot be uninstalled as long as it is set as default language.

I have changed the language to english but the error is always the same.

How can I remove this language extension manually?

Many thanks for your help