Desktop wallpapers are just another way to personalise a MacBook computer. However, storing too many larger image files on your computer can take up needed hard drive space. You can easily change or even delete the current desktop wallpaper from a MacBook. While changing the wallpaper can be undone, remember that deleting wallpaper is permanent.
Select System Preferences from the drop-down Apple menu (the apple icon on your menu bar in the upper-left corner of your computer screen).
Under the "Personal" heading, choose "Desktop & Screen Saver." Click "Desktop." Your current desktop wallpaper image will be displayed, and you can find it among all other images from its source folder. To delete this image, locate the source folder on your hard drive now that you know its name (it is the highlighted folder in the left list of folders, and the name of the image file is listed to the right of the thumbnail picture above the list of folders, directly under the Desktop and Screensaver tabs). Open Finder and put the name of the image file in the search box and your computer should return that file in your search results. You can delete it from your computer there. Alternatively, to simply change the current desktop wallpaper, select from other images stored on your computer, whether they be located in a folder of pictures on your desktop, among the photos in the albums in your iPhoto library or among one of the dozens of wallpapers that come standard with your MacBook, which should be displayed prominently at the top of the list of photo sources.
Close the Desktop & Screen Saver dialogue window, and the settings that you have chosen will have already been applied and saved to your MacBook.
Delete any of the default Apple wallpaper images on your computer by deleting them individually (or collectively) from the "Library" folder on your hard drive. To locate this folder, click the hard disk icon on your desktop. Select "Library" and then the "Desktop Pictures." This is where all of the default Apple wallpaper images are stored.