I have DF set to change the windows logon background to match my desktop wallpaper, but the logon background is not changing. I have checked in the file DF sets as the background (C:\Users\[me]\AppData\Roaming\DisplayFusion\WindowsLogonImage.jpg) and it changes, but the file is not applied to the logon background. I think this is a bug and not my settings, but I am not entirely sure.

Edit: After more more reasearch, I might be having this bug: http://news.softpedia.com/news/Microsoft-Confirms-Lock-Screen-Background-Bug-in-Windows-8-1-Preview-366599.shtml
I would have thought Microsoft would have fixed it by now though.

No, it changes to another random image, but never the one I select. I'm 99 percent sure it is a windows error now and I would delete this post if I could. The preview in the lock screen settings matches up with my desktop background so DF is working like it should. The actual lock screen does not match the preview/lock screen settings, but 8.1 is still unreleased and bugs should be expected.