Problem with custom backrounds

Hi, I'm having a problem when flashing pictures as the 01-12.bmp they always come up white even though i have the dimensions right. i have 3.40 oe-a and trying to flash the theme ultimate black on the easy theme installer. I've also tried flashing through the usb with many other custom xmb's and the backround never works. So i guess my question is, is it my problem or is it a problem with the custom firware?:confused:

you have to go to theme settings then select the first months background, and than reboot the psp and it should show up after that :)

Thanx a bunch that worked + rep for you!