A new look for LightDM, Install LightDM GTK+ Greeter in Ubuntu via PPA

Install LightDM GTK+ Greeter in Ubuntu 14.04 Trusty/13.10 Saucy/13.04 Raring/12.10 Quantal and If you have installed LightDM in Linux Mint 16/15/14

LightDM Gtk+ Greeter used in Lubuntu, it is light-wright interface, the LightDM GTK+ Greeter provides Linux users a quick, reliable, and accessible login screen. With refreshed attention to detail and consideration for accessibility, this is the best release yet!

Features:

• Window positioning (relative or absolute) of the login window and power dialogs is now configurable.
• The default user-image displayed for user's without a profile image is now configurable.
• The onboard on-screen keyboard application is now run in xembed mode.
• The accessibility menu items can now be activated with the F1, F2, and F3 hotkeys.
• The selected user can now be changed from the username and password entries with the up and down keys.
• The power dialogs can now be cancelled with the Escape key.
• Available in GTK+2 or GTK+3
• Support for Ubuntu indicators
• Supports loading user wallpaper and profile image
• Optional and configurable clock
• Named widgets allow for easy customization
• Lock Screen Improvements: When the LightDM GTK+ Greeter is used as a locked, it now blanks the screen when activated.

Changelog:

• Display selected username in tooltip for the user combobox
• Use GtkInfoBar for authentication messages
• Greeter doesn't select user's last session when using "Other"
• Can't change the login window’s position
• Disabling language selector leaves strange artifact on the screen
• Move to password input if pressed after username input
• Support enter key to validate login entry
• Improve "login greeter -> desktop" transition in Xubuntu
• User background gets painted over background specified in config file
• Fixed typo in language selection code
• Fixed keyboard focus when used with the on-screen keyboard

For customization checkout these links page, page2.

To install LightDM GTK+ Greeter in Ubuntu/Linux Mint open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:

Terminal Commands:
sudo add-apt-repository ppa:lightdm-gtk-greeter-team/stable
sudo apt-get update
sudo apt-get install lightdm-gtk-greeter

To install LightDM GTK+ Greeter (Daily Builds - Unstable) in Ubuntu/Linux Mint open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:

Terminal Commands:
sudo add-apt-repository ppa:lightdm-gtk-greeter-team/daily
sudo apt-get update
sudo apt-get install lightdm-gtk-greeter

That's it

Source: Lightdm Gtk Greeter