Seen similar question many times on AskUbuntu, but most answers was bout unity-helpers or gconf ...canonical... etc, so this actually doesn't seem to work.The problem is that I decided to move to lightdm from gdm. Yep, it works,but I can't setup background image to it - always getting black bg color in exchange of picture.My configs:tempos@parmasse ~ $ cat /etc/lightdm/lightdm-gtk-greeter.conf ## logo = Logo file to use, either an image absolute path, or a path relative to the greeter data directory# background = Background file to use, either an image path or a color (e.g. #772953)# theme-name = GTK+ theme to use# icon-theme-name = Icon theme to use# font-name = Font to use# xft-antialias = Whether to antialias Xft fonts (true or false)# xft-dpi = Resolution for Xft in dots per inch (e.g. 96)# xft-hintstyle = What degree of hinting to use (hintnone, hintslight, hintmedium, or hintfull)# xft-rgba = Type of subpixel antialiasing (none, rgb, bgr, vrgb or vbgr)# show-language-selector (true or false)#[greeter]#logo=background=/usr/share/backgrounds/lightdm.jpg#background=#772953#theme-name=Adwaita#icon-theme-name=gnome#font-name=#xft-antialias=#xft-dpi=#xft-hintstyle=#xft-rgba=show-language-selector=trueThe file itself:tempos@parmasse ~ $ ls -la /usr/share/backgrounds/lightdm.jpg-rwxrwxrwx 1 root root 1362684  14 12:36 /usr/share/backgrounds/lightdm.jpg
Change lightdm background
gnome;configuration;gentoo;lightdm
Thanks all.Seems, that it was some bug - in lightdm itself (meening package-specific or some libraries) or, possibly, it was simply installed with some errors/bugs. I'm now trying to install many different things, like compiz, awesome, enlightenment, lightdm and others, so can't be sure.The fact is today both lightdm and lightdm-gtk-greeter received updates, and this fixed background's problems even with original images and config.