Hi,
Thank you for reaching out, and sorry about the trouble you are having with the screensaver. Sometimes the issue occurs when Windows cannot find the folder previously used for your slideshow.
Were you able to check if the slideshow folder was renamed or moved? If Windows can’t find the folder it was using, it will immediately switch the background back to Picture. To fix this, go to Settings > Personalization > Background and select Slideshow. You’ll see the Browse button appear briefly before it reverts; click it right away and choose a new, valid folder with your images. Once you select a working folder, the slideshow setting should stay in place.
I hope that these help. If you need further assistance, you can leave a comment below.
Thank you,