In KDE 4.9.97, a custom wallpaper set in the lightdm configuration dialog is ignored, instead I see a white background. In the config dialog, the thumbnail of my selected wallpaper shows up as expected. What might be related: When the screen is locked, a default wallpaper (some purple-blue stuff, seems to be new in KDE 4.10..) is shown as background, although I did not configure it this way. Reproducible: Always Actual Results: no wallpaper shown Expected Results: configured wallpaper shown This bug appeared after I upgraded to KDE 4.9.97, it worked fine before that.
It's normally one of: - File permissions mean the wallpaper is not readable - /home/you is encrypted and therefore doesn't exist when LightDM is running. There is an existing bug on dealing with this situation, if you can confirm it is caused by one of the two parts above, I will mark this as the correct duplicate. However, I'm intrigued that you said this worked before 4.9.97, so I won't do so just yet.
Thanks for the hint. I can confirm it was a file permission problem and would like to add the wish to either receive a warning in the config dialog of lightdm when selecting a background with insufficient file permissions, or to have lightdm to make a copy of this file with the right permissions so that it can be used.
*** This bug has been marked as a duplicate of bug 305988 ***