Backupper will not restore backup to a larger drive

I have used AOMEI Backupper to make a System Image of a 500 GB HD, which
is partitioned into a 68 GB and around a 430 GB. I had a problem with
the boot getting corrupted on the computer so I have tried restoring my
backup and once I restore it, the computer still will not boot. So, I
took a 640 GB HD and put into the system and tried restoring my backup
to it (the 640 GB is completely wiped and free) and when I try to
restore it I get an error message saying that the drive is not large
enough I still need an additional 823 GB? What? The whole image cannot
be larger than 500 GB because that is the max size the drive was that
the image was made from. So, why would it require an additional 823 GB?