[connorcpu]

There may be a little more to it, but sadly after setting it up for a couple hours, it seems the TrySetLockScreenImageAsync method always returns failure from a non-UWP app :(

If anyone else wants to tinker with it https://gist.github.com/Connicpu/8b092b2c0ad539573b893dbca54...

[voltagex_]

Sorry. Seems it's limited in what paths pictures can be loaded from. Bloody Microsoft.