@IAN MOUNTAIN Wrong screensaver, that option refers to the fireworks screensaver that comes up from inactivity.
Just to clarify, this thread is a bit mis-titled. It isn't primarily about the screensaver, though a few users have complained about that in this thread as well, but the majority of the posts (including OP) are referring to what is probably better titled as a 'desktop wallpaper', the ugly, un-customizable images that cycle through on the 'No Input' screen. If LG is going to force us to look at their lame HDR photo gallery (that doesn't even download new ones from the internet like Chromecast or Windows Spotlight does) instead of just showing a blank screen with the text 'No Input' like every other TV, then at the very least they should let us customize the photos!
If the issue is that the set may burn in if you put in 5 copies of the same image or something, as some have brought up, then they could simply add a disclaimer. They seem to have no problem doing so under the Screen Saver option, as you can see.
As I said in my last post in April, I tried to use the SDK to get into the TV and change the photos. You need root access to get edit permissions to the relevant directories. Tried a few different techniques to try and get root access, but couldn't quite do it so I gave up. But if anyone knows how to properly root an LG TV I'd love to know.