Wallpaper Magica is a desktop wallpaper slideshow program. It was designed specifically for multi-monitor setups.
License: Free
Download (dropbox): WallpaperMagica.zip Version 1.24.94.143
Requires Microsoft .NET Framework 4
Tested on Window 10, Windows 7, and Windows XP* (*XP hasn't actually been tested in a long time, it should still work...)
There is no installer. Extract the ZIP file to wherever you want to run the program from.
To include the program on startup, create a shortcut in the Startup folder in your Start Menu. In the shortcut properties, set Run to Minimized.
Writing large files like this does will eat your SSD. Recommend using an NTFS junction to move C:\Users\[your user]\AppData\Roaming\Microsoft\Windows\Themes to a mechanical drive or RAM disk. Also change the desktop image save location to the same by right clicking the Save button, or use another NTFS junction on C:\Users\[your user]\AppData\Local\WallpaperMagica.
"In theory" this should work on linux with mono or wine?