If that's too difficult/complicated, perhaps amend the DexClock /Wallpaper Clock plugin executable to accept a "wallpaper clock" filename ...
Dexclock is licensed as Freeware for Windows (32-bit and 64-bit) operating system / platform from clocks and calendar without restrictions. Dexclock 1.3.39 is available to all software users as a free download (Freeware). Though marketed as 'freeware&
Dexclock, free and safe download. Dexclock latest version: Beautiful desktop wallpapers with clock functionality. Dexclock is a nice Windows app that turns your desktop wallpaper into something more than just a background
Softshape.com. Powerful program with many features, including wallpaper clock support. Dexclock {Windows} Dexpot If you only want wall clocks, try Dexclock.