NTLite will load install images when they're part of a complete ISO, or as a standalone install WIM or ESD file.
Ghost backs up and restores entire disk images with sparse volume support (to reduce the image's save size). To convert it, you would restore a Ghost image to a target system. Then reboot into Recovery or WinPE, and perform a DISM capture of the system drive.
This captured image becomes your new install WIM, which replaces the same file in the ISO distribution.
If you have a target system that is sysprepped, you can skip Ghost entirely and just DISM capture it directly for NTLite's use.