Background picture


Under KDE, where should be the background picture that you want to appear at each login?


settings > startup and shutdown > login screen

I rephrase my question: in which folder should the image be located?

Any folder. You just select the image you want from any folder.
You can right click an empty space on desktop then select configure Desktop

For clarity, do you mean the background picture for the login screen (Settings > Startup and Shutdown > Login Screen (SDDM)) or the desktop wallpaper (right click on deskop > choose Configure Desktop and Wallpaper…)?

You can choose an image from any folder in either case.

FWIW, KDE wallpapers are stored in /usr/share/wallpapers, and EndeavourOS wallpapers (if you’ve downloaded them from the welcome app) are stored in /usr/share/endeavouros/backgrounds.

Two options. Read details.
From man sddm.conf:

Path of the directory containing face files, face files should be in username.face.icon format.
Default value is “/usr/share/sddm/faces”.

From the linked wiki article:

The other option is to put a PNG image named .face.icon at the root of your home directory. In this case, no changes to any SDDM configuration file is required. However, you need to make sure that sddm user can read the PNG image file(s) for the user icon(s).

Because sddm and kde have been in active development, some of the above need to be verified that work as explained.

Unless you know what you’re doing, I recommend against modifying sddm.conf as that can make problems when starting the GUI session. Use Plasma settings, there you can change the most common settings of SDDM, like theme, background picture, numlock, etc…