How can I change the Login screen theme? Is there a graphical way or no?
Use this command in the terminal:
sudo cp /usr/share/applications/gnome-appearance-properties.desktop /usr/share/gdm/autostart/LoginWindow
Logout, and you will be prompted with the Appearance window. change the theme as you change it for the desktop, and login back, and type this command:
sudo rm /usr/share/gdm/autostart/LoginWindow/gnome-appearance-properties.desktop
This depends on what you want to do with the login screen. You can configure some basic options in the Login Screen Settings app (System/Administration/Login Screen) - whether a user should be automatically logged in, the default session etc.
However to change the login screen more graphically Ubuntu Tweak can be used to change the background, logo etc.
U can use GDMtweak to change theme and Icon. see the link http://www.webupd8.org/2011/05/change-gdm-theme-background-in-ubuntu.html
I'm not aware of a graphical tool to automate the process but is not overly complicated to change the theme of gdm.
Take a look at Gnome-Look GDM, most of the themes there come with good instructions on how to install them.
There is a graphical tool for this. It's called GDM2Setup. You can get it from this PPA: https://launchpad.net/gdm2setup
Theme Support for GDM has been terminated since UBUNTU 9.Sorry..!!
copy the image you want to use into the /usr/share/gnome-shell/theme folder
sudo gedit /usr/share/gnome-shell/theme/gnome-shell.css
Search for the following section
background: #2e3436 url(noise-texture.png);
change the name of the image to your image | set background to repeat or no-repeat
Save the file | logout and your new background is there
This works for the best Ubuntu - Ubuntu Gnome - other editions might not
dconf worked for me on Ubuntu 12.04. Ubuntu Tweak has no longer any (visible) way to change gdm background.
com -> canonical -> unity-greeter -> background
hope this helps, cheers!