|i dont have a ghost exe or the scnario to test but i guess you can add a similer for loop serach for image.gho and when found assign that drive to a variable.|
E.g below can be added.
for %%i in (c d e f g h i j k l m n o p q r s t u v w x y z) do (
if exist %%i:\image.gho set source=I:
echo image file found in drive %%I
later, modify your code to use %drive%: as source drive name..similer to
may be someone can come up with a better idea..