Cable Forum - Something strange

Whenever I reboot, Linux Mint forgets my wallpaper and reverts to its default. I found the folder where it lives (/usr/share/backgrounds/linuxmint), opened it as root, put my wallpaper (renamed to default_background) there, and put every other wallpaper into a folder. In effect my wallpaper is the only file in there, so Mint should display it.

It doesn't. The default wallpaper is still displayed.

I'm new to Linux (not to Unix, but it's been decades since I wrote a script!). What am I missing? Even Win 11 can do better than this.

The Internet is less than helpful. Everything I've tried so far is temporary - every reboot, the default is back.

I've just tried deleting the folder, so default_background.jpg is the only file in there - and the default still appears!

- no, it doesn't; Mint now seems to have decided, "Oh, that's what the user wants!" and is now displaying it after a reboot. Colour me even more confused, but it's what I want, so I'm calling it a win!

---------- Post added at 10:58 ---------- Previous post was at 09:57 ----------

Something else: I specified British spellings when I installed Mint, but Firefox highlights, e.g., "colour" as misspelled, and "color" as OK.

Is this Firefox-specific? I'll call up a file in LibreOffice Writer and see...

Hmm. No, "colour" is not highlighted as misspelled. Idea: check Firefox settings...

- and the default is English (GB). So why is it highlighted as misspelled when, in the UK, this is not incorrect?