Windows Image And Format

I know before you can use a Hard Drive and Copy anything to it even if it is a Second Hard Drive you must Format it.

So lets say you did this and then you Made an Image of Windows on the Second Hard Drive you just Formated.
So now you have a good Windows Image on the New Hard Drive and you keep it.

If the Hard Drive in your System ever goes down I know you just Buy the same Size Hard Drive in GB and Replace the System Hard Drive.

Now you can use the Second Hard Drive with the Windows Image to put back onto the new Hard Drive.
And yes I know how to do this but one thing?

The New Hard Drive that will be put into my System if my Old Hard Drive ever goes down do I have to Format it to before I put the Windows back on it?

Or does the Windows Image Format the New Hard Drive it is going on?