Login Screen/Background Change? (kubuntu)

I have Kubuntu 13.04 (last version) and lightdm

I want to change my login screen background (not my wallpaper after I type my password. I'm talking for the image you see WHEN you type your password). It shows a greyish "image" right now. When I tried to use a picture from home and restarted the screen became white and it didn't show my image. I searched and found out that it because of some setings.

The problem is I'm very new to kubuntu and I don't want to mess things up with complicated setting from the terminal etc or to mess aroud with the root files because I won't be able to fix things.

Is there a simple solution as to how can I change this image? There is no option for me to download something there but only to load a picture.

Thank you very much in advance

Solution 1:

At here

KDE System Settings > Login Screen (LightDM); Theme tab

Background image

and the log in screen has new background.

Why it is not working - White background - Check these

1) The image file has wrong extension

Tested with jpg picture with the png extension. The file properties is showing the right image format.

Right click the file > Properties: Information tab

The picture should have correct extension - If not the LightDM can't read the picture data.

2) The image file has wrong permissions

The user has forbidden the read of the image.

Right click the file > Properties: Permissions tab

The Owner/Group/Others should have the right to read the picture data.