amigo debes de descomentar las lineas que deseas utilizar, asi

Código:
Custom images can be loaded here to be placed anywhere on screen, usually as background
;Set this to an unused icon and use sysgfx (or other method) to replace it with your custom picture
;You can define multiple backgrounds 0-6 to switch automatically according to custom_mode
;Specify either hex code of internal image or folder and name of external image
[IMAGE_FOLDER]: usb/other/Sleep
;[CUSTOM00.ICON]: 0xE5B0;
[CUSTOM00.ICON]: fondo.png
;[CUSTOM01.ICON]: 
;[CUSTOM02.ICON]: 
;[CUSTOM03.ICON]: 
;[CUSTOM04.ICON]: 
;[CUSTOM05.ICON]: 
;[CUSTOM06.ICON]: 
[CUSTOM_MODE]: 0x01; 0=static icon00, 1=sequence by time, 2=random by time, 3=sequence by Day of week(Sunday=icon00, Mon=icon01, etc)
[CUSTOM_TIME]: 0x02; Time period before background changes in minutes