If phone gets TFTP info, then use 1st Image in List.xml as the default wallpaper, and make the phones default firmware image the LAST option in the list.
If the phone does NOT get TFTP, then use the default image.
This would allow anyone to set their company logo on all phones with any firmware push, WITHOUT the need to purchase a 3rd party app to accomplish the same, and without having to lock the phone to one wallpaper with a Common Phone Profile.
You would also be able to quickly be able to see which phones didn't get TFTP info, and registered using the cached config.
CUCM, Gotta Love It !!