If you have created a ghost-like image which should be bootable then it is a binary file from a sector-to-sector copying process.
Such a file must be restored using the original program on the original partition so that the number of sectors matches exactly.
The ghost-image file cannot be restored on a mounted partition as the copying process is done at a hardware level with the controller. It should be restored directly on the block device like /dev/sda1.
As the information is a binary pattern of "1" or "0" there is no filing type involved.
Say if you have created the image called my_image from command
dd if=/dev/sda1 of=my_image
then to restore it would be to reverse the destinations of the input file (if) and the output file (of).
dd if=my_image of=/dev/sda1