Hi, GIL80
Ok this is how it works.
Say your C: partition is 50 GB with only 20 GB used.
Clonezilla will make an image using only the 20 GB of used space and by default use a compression scheme
to greatly reduce the file size to about 50% of the original used space.
So your resulting image in this case would be about 10 GB.
If your using an external hard drive to store your image you can save the image file directly to that during the creation
of the image. You can also restore from that drive as well.
You have to run Clonezilla from a bootable media source like a CD. You can't install it to Windows and run it from there.
There is much info on what Clonezilla can do here
Clonezilla What I would suggest is making a separate backup of your personal data as well as using Clonezilla to image your C: drive.
Even though Clonezilla is linux based it will easily handle making images of NTFS partitions like your Win 7 install.
If you save the image to a fat 32 storage device Clonezilla will automatically split the image into less than 4 GB pieces since fat 32 only supports maximum of 4 GB files.
Restore will recombine those partitions seamlessly.
I'm not sure if you can restore an image stored on a NTFS partition, if not Clonezilla will tell you so.
I will try it to find out.
The reason I mention this is because another linux based imaging tool I used to use would not restore an image stored on a NTFS
volume.
Now here is a slightly risky part and the main reason I mention that you back up your data.
Whenever I make an image I perform a restore right after creating it, while still in Clonezilla to verify the integrity of the image.
This way I know that the image will work when needed.
By the way you cannot create and store an image on the same partition you are trying to image.
Creating an image can take some time depending on the size of the used portion of your partition and the media you save to.
Example: my 10 GB Win 7 install (on a 22 GB partition) takes about 10 minutes to create and store directly to a 16 GB thumb drive.
It restores from that thumb drive in about 4-5 minutes.
UPDATE: just sucessfully restored an image from a NTFS storage partition.
Get familiar with the directions at the Clonezilla web site and if you need more info just ask me.