how do I inject ze_train? keep getting errors

[adversary*D]

I reskined ze_train but when I go to inject it says bitmap being injected must be DXT@ or DXT#. I saved it the same way i save the warthog but this wont work i tried opening the ze_train and just save it then try to inject and it doesnt work only way it works is if it is the original without ever being save what am I doing wrong