If you want to narrow down the photos displayed, feel free to click on any of the other categories/albums in the left menu.

Click Apple in the left menu if you want to use Apple’s desktop backgrounds. Click Photos. If you would rather use your own photos, click on this button in the left menu. Selecting Photos means your background will cycle through all of your photos on iCloud. If you want to narrow the selection down, click on any category/album underneath “Photos. " You may not be able to see these other categories if you haven’t expanded the Photos menu. Do this by clicking on the arrow to the left of Photos. Some of these subcategories can also be expanded (for example, expand the “Albums” subcategory to click on a specific photo album).

You may not be able to see these other categories if you haven’t expanded the Photos menu. Do this by clicking on the arrow to the left of Photos. Some of these subcategories can also be expanded (for example, expand the “Albums” subcategory to click on a specific photo album).