I cam across this Youtube video which I thought is simple to understand even for non-technical folks.
It explains the difference between Cloning and Imaging. And how it can be applied to your backing up of your system drives, or to do system upgrade.
Example : you can upgrade your old HDD to SSD... or move it to a larger storage device etc..
It also talks about Macrium Reflect 7 software which I thought is a very good piece of software.
It's only free for 30 days - trial version.. but enough for you to do your "hdd upgrade"