Trouble Removing Previous Lock Screen Images

Hello all,

I've recently run across a little-addressed problem in Windows 8.1, and that is the removal of old Lock Screen photos. Most everyone knows that in Windows 8, it was as simple as a right click to clear out the Lock Screen image cache, but that feature has since been removed in 8.1. My question is, how would I go about removing the old images? I've tried deleting the LockScreen_"Letter"​ folders in the C:\ProgramData\Microsoft\Windows\SystemData folder, but that produces an undesired result (all lock screen images disappear). I've tried "Refreshing" and completely restoring my PC with no success. Has anyone done/attempted this? Is there a simple fix or registry tweak that I've missed?

Thanks in advance!


Here is the result of deleting any of the LockScreen_"Letter"​ files.