|To clarify the above, you need to clone/image the partition in order to use that file to restore the partition to the state it was in at the time you made the image. |
You should maintain back ups of your personal data on an ongoing basis. You can always re-install Windows and your programs but you can't replace photos, purchased music, self created documents, etc. Get in the habit of copying those types of files immediately.
The main reason to image a partition is for convenience in the event you must re-install due to malware or hardware failure
You may want to consider setting up your hard drive using additional partitions. I recommend at least three partitions and more if you dual boot. C partiton contains the OS and a few key programs. Second partition contains all remaining installed programs. Third partition is for personal data.
The advantage is ease of maintaining those images. If the worst should occur and you need to restore your OS all your other partitions will function just as they did prior to the restore without the need to actually restore them. You must make separate images for each partition. Your personal data doesn't need to be imaged but simply copied. Imaging will not compress the files much because for the most part those files are already in a compressed format. Jpg & MP3 for instance won't compress much further, if at all.
If you have a pre-configured computer like an Acer, Sony, Dell, etc. Be sure you have restore disks so you can reform a factory restore in case of a hard drive failure.
Once you have that restore set you can wipe and repartition the drive if you wish too. Adding a second hard drive can be useful too.
Imaging the drive is NOT a replacement for those disks. Dell computers may ship with disks. Most other brands require you to make your own and strongly encourage you to do so when the computer is first put into service. If you haven't yet done that it is not too late.
Another useful tip is this. When buying commercial software burn a copy of the disk immediately and then use the copy to install. That way you have a back up you know works. Making an archive copy of any of your commercial software is perfectly legal.