Sony PSP-1003 - Manual (Page 101)

101
Settings
Theme Settings
You can change the theme for the PSP™ system screen or display an image as
wallpaper.
You can change the background colour of the screen. Use the directional
buttons to select a background colour, and then press the
button to complete
the setting.
The default setting for the menu item is underlined.
You can select between displaying and not displaying wallpaper.
The default setting for the menu item is underlined.
Theme Settings
Theme
Original Changes automatically to a preset colour each month
Colour swatches Sets to the selected colour
Wallpaper
Do Not Use Sets to not display wallpaper
Use Displays the image set as wallpaper under ( page 75)