Hello p5200,
A system image is not incremental like a
backup. Each system image created is a separate full backup period. There's no need to delete the old one first unless you just wanted to since it'll be automatically deleted as needed to make space for new image backups.
http://www.sevenforums.com/tutorials/663-backup-complete-computer-create-image-backup.html
Hope this helps,

Shawn
You might need to explain this to me.
When I was testing Win 7 system image suitability, it made different image versions.
They were selectable in the restore.
And appeared to be incrementals.
So let's say my first full image showed 15gb in the WindowsImageBackup directory.
Taking a subsequent image might take the WindowsImageBackup directory to 16gb.
And was much faster.
As I recall I took about 7-8 system images over some period of weeks.
I could select any of them to restore - they were time-stamped.
As I recall, I tested restoring older versions successfully.
But the total size of the WindowsImageBackup directory never went beyond about 28gb.
I was okay with that, because it saved space.
With subsequent testing I found that copies of the directory weren't portable, in the sense that the restore could only address all image versions in the WindowsImageBackup directory on the original drive the images were made to.
With any WindowsImageBackup copied to a different drive, restore would only see the last image, losing previous versions.
There may be a way to restore that addressability, but I didn't need "incrementals" enough to bother looking.
I rejected the Win 7 and use Ghost 15. Tried Macrium, but Ghost was considerably faster.
But it's my firm impression that Win 7 system images taken with Win 7 are "incremental."
Is that wrong?