How can I change the Kubuntu background from default?

Question

Can SOMEONE please tell me how to change the default background in Kubuntu 12.04? I have managed to select a rather nice wallpaper for my desktop, but I CANNOT change the background for the splash screen, lock screen or login screen. I am using the lightdm-kde-greeter because I think it looks nicer than the default, but as I have said, it just REFUSES to allow me to change my default, wallpaper (the grey one - why they chose grey I will never know). If I choose "classic" lightdm greeter theme it works, and I can change my login screen background but not my splash screen, and if I choose user bar I cannot even change background.

Here is what I have tried so far:

1. System Settings, Login Screen (LightDM). Choose my image for the background under Classic and apply the changes, then switch to User Bar. This did not work.
2. System Settings, Login Screen, disable Themed Greeter, then choose background image, and re-enable themed greeter. This didn't work either.
3. Going in as root to /usr/share/wallpapers, deleting the link called kubuntu-default.png and recreating it pointing to my chosen image. This did not work either.
4. Deleting my cache from /var/tmp. Again, this did not work.

Can someone advise me, I'm starting to go mad here!

Answer 1

This seems to be a bug. If you run this from the terminal:

$ kcmshell4 kcm_lightdm

you get warnings about invalid permissions (even if you run it as root), and at the end the message:

kcmshell(2213) LightDMKcm::save: save failed: ""

About the splash screen: which one do you mean? KDE's login splash screen or the system bootup splash screen? KDE's splash screen can be changed by installing a new theme, for the system's splash screen check here: What alternatives are available to replace the purple boot splash screen?

Answer 2

Given up on 12.04. I just installed 13.10 instead. It's not an LTS release but I don't mind waiting for 14.04 as my next LTS! :-)