Select Menu > Ctrl. panel > Themes.
Select from the following:
General - Change the theme used in all applications.
Menu view - Change the theme used in the main menu.
Standby - Change the theme used in the home screen.
Wallpaper - Change the background image in the home screen.
Call image - Change the image displayed during calls.
Audio themes - Set sounds for various device events.
To activate or deactivate the theme effects, select General > Options > Theme effects.