On you TFTP server, create the directories:
Desktops\320x212x12
In there you make a file "List.xml"
FTP:Desktops/320x212x12/TN-Logo.png" URL="TFTP:Desktops/320x212x12/Logo.png"/>
(File should have 3 lines)
Then, make TN-Logo.png (80x53 in size) and Logo.png (320x212 in size).
Restart your TFTP service, and then your phone.
Good luck!