A clone is an exact copy and the same in size. An image is a compressed copy. They both will do the same thing. It is just more practical to use an image. I backup my drive every week so I can only get a certain number of images on my backup drive before I start deleting the older ones. If I used clones, I could not get as many on my backup drive.
Just an FYI;
Disk Cloning:
Disk cloning is the process of copying the entire contents of one hard drive to another including all the information that enables you to boot to the operating system from the drive. A cloning program enables you to make a one-to-one copy of one of your computer's hard drives on another hard drive. This second copy of the hard drive is fully operational and can be swapped with the computer's existing hard drive. If you boot to the cloned drive, its data will be identical to the source drive at the time it was created. A cloned drive can be used to replace its source drive in a computer in the event that something bad happens to the original drive.
Disk Imaging:
Disk imaging is the process of making an archival or backup copy of the entire contents of a hard drive. A disk image is a storage file that contains all the data stored on the source hard drive and the necessary information to boot to the operating system. However, the disk image needs to be applied to the hard drive to work. You can't restore a hard drive by placing the disk image files on it; it needs to be opened and installed on the drive with an imaging program. Unlike cloned drives, a single hard drive can store several disk images on it. Disk images can also be stored on optical media and flash drives.
HTH
Cloning is a real time transfer from one hard drive to another. The receiving hard drive should boot if all went well. Think of it as a single operation. It's isn't a backup in the normal sense of the word and is typically used when all is well and you want to move from one working system to another.
Imaging has two operations: 1: you make an image file of a partition and store it on some other partition. It's just a file like any other file and isn't bootable. 2: at some future point, you "restore" that image file to a partition. It's the restoration process that makes the receiving partition bootable and usable. When you want to restore, you must boot from disk or USB drive that you prepared previously. If you can't boot from this disk or USB drive, you can't restore.
It's a backup as normally understood. You can make and keep an image file for every day of the week if you want and later restore whichever of those you want. You might restore an image after a hard drive failure, after a major virus attack or unknown corruption, or after buying a new hard drive.
They have some similarities, but imaging is more flexible and less prone to failure.
I believe your explanation warrants a caveat; Using a cloned drive in another system, as you state, will generally be problematic due to differences in drivers and licensing. Cloning is very often used to replace a spinning disk with a newer state of the art SSD in the same system.
If I may just add a smidgeon to all the excellent info above. I am a "Gregrocker follower" insofar as a clean install of Windows 7 is concerned. When everything is running exactly as I want it to I use Macrium Reflect to create an image so that I can always very easily go back to that perfect install. Saves hours of work and has worked for me on my own and a number of friend's PC's. One thing to remember always verify the image to make sure it is good. Then do the whole thing again so you have two copies just in case the first one doesn't work.
Quote