A hard drive image is actually a backup of one or more partitions, including the partition-size & type. Therefore, when it's restored it has to "replace" or overwrite the existing partition and data on the target partition.
You can't restore a backup image and still preserve the existing partition and data on the target.
Thanks for that clarification. On my old computer I had two partitions, C and D, each having XP Pro installed and using dual-boot option. However, I created separate disk images for each of the partitions
Is there any way to combine the Macrium disk images or would I be able to use XP with single boot by restoring the images separately?
From your explanation I surmise that if I restore the image to a new external drive, it should work. Is that true?
Thanks for your help.