Reader Anna Howarth seeks to beautify her desktop. She writes:

I love some of the images that appear in Apple’s Aerial screensaver collection. Some of them also appear as Desktop backgrounds, but not all of them. Is there some way I can use them as my Mac’s background pattern?

There is. In the Finder choose Go > Go to Folder (Shift-Command-G), enter /Library/Screen Savers/Default Collections/ , and click Go. In the resulting window you’ll see four folders—1–National Geographic, 2–Aerial, 3–Cosmos, and 4–Nature Patterns. These folders hold all the images for the screensavers of the same name.

There are a couple of ways to make them available to you as Desktop backgrounds. The first is to select an image and choose Finder > Services > Set Desktop Picture. Do so and the image will appear as the background.

Or, launch System Preferences, select the Desktop & Screen Saver preference, click the Desktop tab, and drag those four folders into the bottom of the image selection area. When you select a folder here the images it contains will appear on the right. Select the one you want to use as your Mac's desktop background.