: Right-click your desktop and select Personalize . Under the "Background" section, find the "Choose a fit for your desktop image" dropdown and select Span . This forces the wide image to stretch across all connected displays instead of repeating on each.
For a more dynamic "Planets" experience, third-party software offers enhanced control over triple-wide setups: How To Extend/Span Your Wallpaper Across Dual Monitors
A is a specialized ultra-wide format typically used for triple-monitor setups or high-end super-ultrawide displays. When applying a "Planets" theme at this scale, the primary goal is often to create a seamless, expansive view of the cosmos that transitions naturally across your physical monitor borders. Setting Up Your Workspace