Changing your desktop or lock‑screen wallpaper in Windows 11 should be one of the simplest customizations you do — but the split between desktop and lock screen, multiple wallpaper modes (Picture, Solid color, Slideshow, Windows Spotlight), and a handful of small system quirks can turn a one‑click job into a troubleshooting session. This guide compiles every built‑in and common third‑party method to change wallpapers on Windows 11, explains the options and best image sizes, and walks through...