Lock Screen photo has gone/Windows throws me out after a short time

I ran Reset/System Restore on my laptop ten days ago, on the advice on an expert in another forum. It replaced my Windows 10 and I'm now finding new problems. These are the two latest:
(1) The photo I'd added to my Lock Screen had disappeared. How do I add it, please?
(2) I'm logged out of Windows after five minutes or so & have to log back in. I've checked my Power settings and they show as per the following snip. Am I looking in the wrong place? How do I keep my laptop logged in, please?



19043.1151

Lock screen image: perhaps you're thinking of Option 1, 4 in this tutorial?
Change Lock Screen Background in Windows 10

I'm logged out of Windows after five minutes or so

Are you certain you are logged out, or are you merely required to enter credentials as a result of the PC going to sleep, for example?

For example, after you log in again, does it take time for your startups to run again, or is everything displayed straight away as when you resume from sleep?

If sleep, I posted some ideas here. Feel free to find more - the poster never bothered to reply.
How to Stop sleep/lock mode every 5 mins!