Microsoft has added a new theme pack to the Microsoft Store for Windows 10 users. Titled Modern Art PREMIUM, the new theme pack contains 12 high-quality 4K wallpapers, the description of which reads as follows:
Explore a new perspective with these 12 images of contemporary art. These premium 4k images are free for Windows 10 Themes. These images are to be used as desktop wallpaper only.
After downloading the collection, go to Start > Settings > Personalization > Themes and click on the theme you prefer.
To apply and change to the most appropriate color, based on the current wallpaper, go to Customize > Colors > Automatically select a primary color from the background.