If you click one, the full-size version will be downloaded. On Windows, open the folder it's downloaded to (usually named Downloads), then right-click the file and choose to set it as your desktop background.
Minimal Mary 3840x2160 / 1920x1080 |
Mary's Imagination 3840x2160 / 1920x1080 |
If you're a Windows user, you can use wallpapers that automatically change appearance based on what time it is, letting you view Mary's world's sunsets as the sun sets in real life.
To use these wallpapers: