Is it possible to delete Windows.Old folders. What is in them at all? Only old folders of past Windows?

Question

Windows

There the user has four folders with the old Windows. He did not format when he installed a new one, and as I understand it, all this can be deleted there. And then they are afraid that the photos are deleted, and all these folders weigh 35 GB. And the pictures should be stored on another disk.

Answer 1

Is it possible to delete Windows.Old folders.

You can if you don't need them.

What is in them at all?

Old OS files to restore the old system.