The short explanation is that I'd like to have the lock screen on my Windows 10 systems behave like the desktop background slideshow, only displaying one image at a time, (ideally) crossfading between them, and not tiling, cropping, or zooming.
I've got a number of custom desktop background images derived from astronomy images (mostly composites). By their very nature, they can't be auto-cropped or zoomed and still look reasonably good simply because I've already cropped them such that there's essentially nothing but the subject anywhere in the picture. As a result, when tilted or zoomed by the lock screen slideshow in Windows 10, they look pretty bad (tiling in particular often results in it looking like one very poorly made composite mosaic). I would really love to have these backgrounds playing on the lock screen in a slide show, but there's no point if they look horrible half the time.
If anyone knows of a way to do this on WIndows 8 or 8.1, that may actually be helpful here too (not much has changed about the lock screen in 10 relative to 8 and 8.1).
Also, while I would prefer a solution involving static settings (even if it's a registry or GPO hack), I'm also open to scheduling a PowerShell script to do this (I just don't have the skill with PowerShell to get something like that working).