Hello all!

I spent way too much time trying to figure out how to do this, but I finally have, so I thought I'd share. I'm pretty new to linux myself, but you'll need to be fairly familiar with navigating around the file system. I'm going to show you how by using the graphical file browser (nautilus). You can use either one single picture, or three different ones in this method. There may be better ways to do this, but this is what worked for me as a newer user.

You'll be navigating the file system as the root user so BE CAREFUL!

These first set of instructions are for using the stock gnome background. Mine had horizontal blue stripes.

First, you need the .jpg file you want to set as your background. Make sure its the same size as the resolution you use for your display.

If you want to find the folders you need first and get familiar with navigating to them, open the normal file browser and navigate to the path below without root access.

open up a terminal window and get root access by typing in

Code:
su -
once you're logged in, open the graphical file browser as root.

Code:
nautilus &
now, browse (carefully!) through the file system to:

Code:
/usr/share/themes/Adwaita/backgrounds/
You should see three .jpg images here:

bright-day.jpg
good-night.jpg
morning.jpg

so, go ahead and right click on each file and rename them to something else. I simply put another character in front of the name to back them up. (xbright-day.jpg)

copy and paste your new .jpg background here and rename it to match one of the three files mentioned above. We're replacing the files we just renamed. Do this again for each of the file names listed. You could also use three different pictures if you wanted, and they'll switch at different times of the day (I think).

Go back out to the login screen and you should see your new background there!

If you're brave, there is an .xml file in this folder called adwaita-timed.xml that you could also edit to just match your file name that you placed into that folder for each entry. I figured I'd start simple. If you do this, make a backup copy of the .xml file first before you modify it!

If you're using the Gnome login screen that comes with opensuse, you likely have the green background. To change those ones instead, go to:

Code:
/usr/share/backgrounds/lightrays/
and modify the files in the same way I mentioned above. You'll notice however, that there are different files for different resolutions, so, I haven't tried it yet, but I think you just modify the file of the appropriate resolution. They're also named differently. I'm sure you know to change them to the file names in this folder, not the ones I talked about above! If your resolution isn't there, you may have to play around a bit to find the one that is being used instead, such as 1920x1080 when you're using 1680x1050.

There's also an xml file here that could be modified too. Thats next on my to-try list!

I hope this helps someone else out and saves them a lot of time poking around! I may be back to edit this if I discover a better way to go about it.