Choose New Wallpaper
To open the Desktop preferences window, click the Apple menu, select System Preferences, and select the Desktop & Screen Saver option. Select the genre of picture required from the left column.
Click on the image you’d like to use for your wallpaper. The desktop is updated immediately, so if you’re happy with the selection, just close the window. If not, choose another.
If you change your mind and want to go back to the desktop you were originally using, just find it among the wallpapers on offer, and click on it to restore it again.
The first two wallpapers are dynamic; changing in brightness throughout the day. Location Services must be on. You can change the desert desktop to an ordinary pic using the pull-down menu.
Use an Image from your Photo Library
As well as having a great collection of images already supplied, you can also use one of your own photos as a desktop image.
Open the desktop preferences: Apple menu > System Preferences > Desktop & Screen Saver. Select the Photos item in the directory list, click the small arrow icon to open it.
Select one of the options within to display any images found. Click on the required image to set it as your desktop’s wallpaper, as you can see here.
How to Add your own Folder to the Folder List
To open the Desktop preferences, click the Apple menu and select System Preferences. In the System Preferences window, select the Desktop & Screen Saver option.
Click the ‘+’ icon which is below the directory list on the left of the window to display a Finder window. Navigate to the required folder, select it and then press Choose.
The required folder should now be visible in the Folders section of the directory list. Select your favourite image from the thumbnails, then close the window.
Automatically Change the Wallpapers
You can even have your Mac regularly change your desktop image to something new. Try it, it’s fun!
The wallpaper can be set to change from every five seconds to once a day. It can even be set to change when you log in, or when waking the computer from sleep mode, so you should be able to find something suitable.
Once you’ve selected a time option, you can opt to display the images randomly or simply work through sequentially by checking or unchecking the Random Order option. Close the window and enjoy your desktop slide show.