Bug#655328: gdm3: Your mistake.

[Sergio Cipolla]

Package: gdm3
Followup-For: Bug #655328

Your mistake, my friend.
You can change the background picture or just use a simple colour by
editing /etc/gdm3/greeter.gconf.defaults or /etc/gdm3/greeter.gsettings
Those files overlap one another (one has GNOME 2 style and the other
has GNOME 3 style), try to see which one works or do as I do and edit both.
For greeter.gconf.defaults
/desktop/gnome/background/picture_filename			/path/to/picture.png
/desktop/gnome/background/primary_color				#000000

For greeter.gsettings
[org.gnome.desktop.background]
picture-uri='file:///path/to/picture.png'
primary-color='#000000'

-- System Information:
Debian Release: wheezy/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'testing'), (1, 'experimental')
Architecture: i386 (i686)

Kernel: Linux 3.1.0-1-686-pae (SMP w/1 CPU core)
Locale: LANG=en_GB.utf8, LC_CTYPE=en_GB.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages gdm3 depends on:
ii  accountsservice                       0.6.15-2
ii  adduser                               3.113
ii  dconf-gsettings-backend               0.10.0-3
ii  debconf [debconf-2.0]                 1.5.41
ii  gconf2                                3.2.3-1
ii  gnome-session-bin                     3.2.1-1
ii  gsettings-desktop-schemas             3.2.0-2
ii  libaccountsservice0                   0.6.15-2
ii  libatk1.0-0                           2.2.0-2
ii  libattr1                              1:2.4.46-5
ii  libaudit0                             1.7.18-1
ii  libc6                                 2.13-24
ii  libcairo-gobject2                     1.10.2-6.2
ii  libcairo2                             1.10.2-6.2
ii  libcanberra-gtk3-0                    0.28-3
ii  libcanberra0                          0.28-3
ii  libdbus-1-3                           1.4.16-1
ii  libdbus-glib-1-2                      0.98-1
ii  libfontconfig1                        2.8.0-3
ii  libfreetype6                          2.4.8-1
ii  libgconf2-4                           3.2.3-1
ii  libgdk-pixbuf2.0-0                    2.24.0-2
ii  libglib2.0-0                          2.30.2-4
ii  libglib2.0-bin                        2.30.2-4
ii  libgtk-3-0                            3.2.3-1
ii  libpam-modules                        1.1.3-6
ii  libpam-runtime                        1.1.3-6
ii  libpam0g                              1.1.3-6
ii  libpango1.0-0                         1.29.4-2
ii  librsvg2-common                       2.34.2-2
ii  libselinux1                           2.1.0-4
ii  libupower-glib1                       0.9.15-1
ii  libwrap0                              7.6.q-22
ii  libx11-6                              2:1.4.4-4
ii  libxau6                               1:1.0.6-4
ii  libxdmcp6                             1:1.1.0-4
ii  libxklavier16                         5.1-2
ii  libxrandr2                            2:1.3.2-2
ii  lsb-base                              3.2-28
ii  metacity [x-window-manager]           1:2.34.1-2
ii  policykit-1-gnome                     0.105-1
ii  upower                                0.9.15-1
ii  xfce4-session [x-session-manager]     4.8.2-3
ii  xfce4-terminal [x-terminal-emulator]  0.4.8-1+b1
ii  xfwm4 [x-window-manager]              4.8.3-1
ii  xterm [x-terminal-emulator]           276-2

Versions of packages gdm3 recommends:
ii  at-spi                 <none>
ii  desktop-base           <none>
ii  gnome-icon-theme       3.2.1.2-1
ii  gnome-power-manager    <none>
ii  gnome-settings-daemon  3.2.2-2
ii  x11-xkb-utils          7.6+4
ii  xserver-xephyr         2:1.11.3.901-1
ii  xserver-xorg           1:7.6+10
ii  zenity                 3.2.0-1

Versions of packages gdm3 suggests:
ii  gnome-mag             <none>
ii  gnome-orca            <none>
ii  gok                   <none>
ii  libpam-gnome-keyring  3.2.2-1
ii  metacity              1:2.34.1-2

-- Configuration Files:
/etc/gdm3/greeter.gconf-defaults changed:
/desktop/gnome/interface/gtk_theme					Adwaita
/desktop/gnome/interface/icon_theme					Mint-X
/desktop/gnome/background/picture_filename			/usr/share/xfce4/backdrops/xfce-stripes.png
/desktop/gnome/background/primary_color				#152233
/desktop/gnome/peripherals/mouse/cursor_theme		DMZ-White
/apps/gdm/simple-greeter/logo_icon_name 			computer
/apps/metacity/general/compositing_manager			false
/apps/gnome-power-manager/ui/icon_policy			never

/etc/gdm3/greeter.gsettings changed:
[org.gnome.desktop.interface]
cursor-theme='DMZ-White'
gtk-theme='Adwaita'
icon-theme='Mint-X'
[org.gnome.desktop.background]
picture-uri='file:///usr/share/xfce4/backdrops/xfce-stripes.png'
primary-color='#152233'
[org.gnome.power-manager]
icon-policy='never'


-- debconf information:
* shared/default-x-display-manager: gdm3
  gdm3/daemon_name: /usr/sbin/gdm3