I made a Python program which carefully stitches top wallpaper from r/EarthPorn to the exact specification of any complex multi-monitor setup.
Different resolutions, relative positions, orientations, and font scaling are all supported. Full-sized images are cached and fit to individual monitors. Photographs will never be distorted.
The program is packaged as a single command-line Windows 8–10 executable (thanks PyInstaller), which persists to update wallpaper on a schedule.
Internally it uses AutoHotkey to extract monitor information, Pillow to fit and stitch photos, SetProcessDpiAwareness to support font scaling, and IDesktopWallpaper to update and
Span the background (SystemParametersInfo cannot).
Technically any site on the SFWPornNetwork will work, but you’ll need to drastically slow down the update schedule to avoid outpacing the less active subreddits (the app will notify you if you do).
Double click to run with defaults, or open from the command line with
--help to see all options.
Backgrounds cycle between monitors by default.
Middle click to read a background’s description and source.