Press s> w Settings > Personalize > Wallpaper.
options
Picture Press Sup or down to select a picture, or select None for no wallpaper.
Layout Select Center to center the image in the display, or Tile to repeat the image across the display.
themes
A phone theme is a group of image and 
sound files that you can apply to your phone. Most themes include a wallpaper image, screen saver image, and ring tone. Your phone may come with some themes, and you can download more.
To apply a theme, press s> w Settings
>Personalize > Themes.
28customize
screen appearance
To choose a color style that sets the look of your phone’s screen:
Press s> w Settings > Personalize > Color Style.
To adjust screen contrast:
Press s> w Settings > Initial Setup > Contrast.
To set screen brightness:
Press s> w Settings > Initial Setup > Brightness.
To save battery life, your keypad backlight turns off when you’re not using your phone. The keypad backlight turns back on when you open the flip or press any key. To set how long your phone waits before the keypad backlight turns off: