The Shifting Background
macOS features “Dynamic Wallpapers” and a built-in rotation tool. Dynamic wallpapers automatically shift their lighting and colors based on the time of day (e.g., a bright desert scene at noon, a dark starry sky at night). Furthermore, the rotation tool can be set to automatically cycle through an entire folder of images every few minutes or every time you wake from sleep. While this provides variety, it can be highly distracting for creative professionals. If you are doing color grading, photo editing, or simply prefer a static, predictable workspace, having the background suddenly shift colors or change entirely breaks your concentration and alters your perception of on-screen colors.
Locking the Wallpaper
To maintain a consistent visual environment and stop macOS from automatically changing the desktop wallpaper, you must disable the rotation and select a static image profile.
Click the Apple logo in the extreme top-left corner of your screen and select System Settings. In the left-hand navigation sidebar, scroll down and click on Wallpaper. First, if you are using a Dynamic Wallpaper (indicated by a small split-circle icon in the thumbnail), look at the top of the window for the dropdown menu usually labelled “Dynamic.” Click it and change the selection to either Light (Static) or Dark (Static). Next, if you had a folder rotation enabled, scroll down to the bottom of the right-hand panel where your custom folders are listed. Look for the “Auto-Rotate” toggle switch or dropdown menu. Click the toggle to turn it Off (or set the frequency dropdown to “Never”). Finally, click on a single, specific image thumbnail to apply it permanently.