Windows – Restore Windows 7 system image from exFAT formatted external hard drive

My system setup is as follows:

C:\ NTFS formatted internal (SSD) boot drive (Windows 7)
D:\ NTFS formatted internal data drive
I:\ exFAT formatted external backup drive

I periodically back up data from D:\ to I:\. I have recently started to use Windows 7 backup to create system images of C:\, but it will not let me create the image directly to I:\ because:

"This drive cannot be used to store because it is not formatted with NTFS"

So instead I create the system image to D:\ and then manually copy it from D:\WindowsImageBackup to I:\WindowsImageBackup, as Administrator.

I am assuming that Windows Backup thinks that any non-NTFS drive is incapable of storing files > 4GB, hence rejects non-NTFS file systems. My question is would the integrity of the image stored on I:\ be maintained i.e. would there be any problems with restoring from the exFAT formatted drive? The only true test would be to attempt to restore from I:\WindowsImageBackup but I don't particularly want to attempt a restore if there are known issues and risks. Furthermore I don't want to have to reformat I:\ as NTFS and recopy all the data over if there isn't really a problem with exFAT.

Experiences appreciated.