Well, the whole idea behind an "image backup" is that it is a photograph of any complete drive (C, D, E, etc.) and all of its contents. The backup can then be used for an "image restore" and the resulting drive (C, D, E., whichever you choose to restore) will be an exact duplicate of the state of things on that drive when the "photograph" was taken.
So, if you have an image backup of your C drive (from the factory, or soon afterwards and before you began customizing Windows and installing 3rd-party software, etc.) then if you choose to restore it you get back to EXACTLY whatever that image contains. C after the restore will look EXACTLY as it did going into the backup. D, E, etc., will be completely untouched from what they look like right now, since they weren't in that "photograph" image backup of C
Now as to whether or not you will have to reinstall all of your 3rd-party software and re-customize Windows after the restore, I would say to you that depends on when you took that image backup. If it was provided to you by the factory as a tool for restoring the state of C to exactly how the machine left the factory, i.e. as it looked the first time you powered it on, then yes... if you now choose to restore it you will "be back to factory" on C. Everything will have to be done all over again, exactly as it was after you powered it on for the first time.
On the other hand if the image backup was manually taken by you at a point later in time, say after you'd completed all of your customization and 3rd-party software installs, then no you won't have to reinstall things all over again (assuming you're satisfied going back to the state of things as they were when you took that image backup). In fact you will be back on C to exactly how the "photographic state" of things looked when you took the image backup. You are restoring that photograph to C.
Again, current contents D, E, etc., are unaffected by the image restore of C. But of course it is C where your programs and "user data" are kept. Any "private data" you've placed on your other partitions is fine and unaffected, but all normal program folders and "My Documents" and "My Pictures" etc., those are all in the C:\Users folder on C... and therefore will also be restored as part of the photograph you are restoring.
My recommendation: going forward do NOT use the image backup/restore functionality built into Windows. It is severely limited in its design and functionality, and can only retain one image at a time on a backup volume (i.e in that folder on D you mentioned where the image of C is located).
Instead I would STRONGLY URGE YOU to go forward using
Macrium Reflect Free for your "system image" tool. It is free, easy to use and intuitive, not to mention powerful and function-rich. And it supports ANY NUMBER OF IMAGE BACKUPS (typically located either on a second physical internal drive, or on a large external USB 3.0 drive of about 2TB used to hold your backups). And if you use the external USB drive method you can then use Macrium Reflect to also backup your D, E, etc. partitions to the same external USB drive.
If you don't want to cry if you lose data, then you must perform regular systematic and adequate/complete backups (either FULL and/or INCREMENTAL), automatically scheduled and performed nightly/weekly/monthly without your having to think about it. You need proper software to do this, and you need adequate target backup medium (like a 2TB external drive) to hold sufficient older generations of backup images to satisfy the occasional situation where for some reason the latest backup is not really the one you want to restore from, but an older backup is.
That's what Macrium Reflect Free can do for you... all of these things.
Note that Macrium Reflect also comes in a non-free version for a modest price. The
Home Edition includes additional functionality over the free version, most notably a folder/file "data" backup capability that is used to backup and restore selected/all "data". This faciltates being able to recover previous individual data folders/files you may have accidentally deleted or corrupted or lost or whatever, from as many older generations of these folders/files backups you might have retained as part of your backup regimen.
Part of the program setup is to define how many older generations of each backup you care to retain before automatically deleting the oldest generation in order to now create the newest one. This applies to both "system image" as well as for "folders/files".
A good backup regimen consists of BOTH types of backups: (a) complete drive (i.e. partition) "system image" for C and possibly also D, E, etc., as well as (b) "data" backups for folders/files across all drives in order to provide convenient easy recovery of specific selected folders/files as might occasionally be needed from either the latest or an appropriate older backup dataset.
The purpose of this backup regimen is to allow you to recover from unexpected major or minor disasters, or simply "lost file" situations, by having a very recent backup available. You won't have to go back to "factory" (unless you've retained that very early backup image and really DO want to start over from scratch) to get you out of your disaster. You only have to go back to last night, or last weekend, or last start-of-month, etc., depending on how often you perform your backups and how many generations you retain.
Finally, I offer a second backup software product, which also can support both "system image" as well as "data folder/file", named
NovaBACKUP PC from NovaStor (again, not free but modestly priced). It has (in my opinion) a much superior GUI and functionality to Macrium Reflect for "data folder/file" backup/restore. But for "system image" GUI and functionality you can't beat Macrium Reflect.
So I use BOTH of these products, combined to perform my complete monthly/nightly/weekly backup regimen... of BOTH types. And both types are automatically scheduled (via setup) to run completely unattended, producing backup files in folders kept on my 2TB external USB 3.0 backup drive. I take "system image" backups of C twice-weekly with Macrium Reflect, in order to guarantee that I always have a very recent image of a "working Windows" that is problem-free.
And I take regular monthly FULL "data" folder/file backups (of all folders/files on all partitions) with NovaBACKUP. And I take regular nightly INCREMENTAL "data" backups with NovaBACKUP, of just those data folders/files that have been created or updated on any partition in the past 24 hours. This guarantees that I can always recover ANY data folder/file from no older than last night at worst, but also optionally selectively recovering any folder/file from ANY DATE IN THE PAST FEW MONTHS.
That's my pitch.
