I tried to Create a system image by [clicking "Create a system image" on the left on Backup and Restore (Window 7) ...
There's your problem.
In the first place, Backup and Restore (Windows 7) is not supported for creating new backups. It was included in Windows 10 for people who were upgrading from Windows 7 and wanted to restore a backup made with Windows 7 to Windows 10.
More to the point: Windows 10 doesn't have a supported image backup utility. There's nothing to stop you from making a backup image with Windows 10, but there's no guarantee that it will work properly, and if you do run into a problem, there's no official solution. That sort of goes against the whole idea of making an image in the first place.
No need to take my word for it. Here's what Microsoft has to say about it:
"We recommend that users use full-disk backup solutions from other vendors."
Finally, the whole point of making an image is being able to reliably restore that image when you need it. So perhaps try this test: After you've finished making an image with Backup and Restore (Windows 7) - if you succeed in doing that - try restoring that image. Next, do the same thing with commercial image backup software. Now compare the two experiences and decide for yourself which method is more convenient and likely to be more reliable in the future, when you'll need to restore your backup. That's how to make the choice that's right for you.