Desktop backgrounds, or wallpapers, are images that appear on the background of the GNOME desktop. One can select any image or colour to appear as the desktop background.
To alter the desktop background, open the Desktop Background Preferences dialog, by right-clicking on a space on an empty space on the desktop, and selecting Change desktop background from the menu that appears. The Desktop Background Preferences dialog will then appear. The dialog contains a list of default backgrounds, or backgrounds that have been used before.
To select a new image as the desktop background, click on the Add Wallpaper button. A file dialog will appear, and finding and selecting an image from your computer, and then pressing Open will add an entry to the list on the dialog, which can be selected to change the desktop background. Alternatively, one can drag and drop an image from the desktop or the file manager, onto the list, to add an entry.
Desktop background images can appear in the centre of the screen, fill the screen, be scaled fit the screen, or tile to fill the screen. To change how the desktop background behaves, one can use the drop-down menu labelled Style, which appears underneath the list of desktop backgrounds.
To select a plain colour, with no image, as the background, scroll to the top of the list of backgrounds, on the Desktop Background Preferences dialog, to find the entry labelled No Wallpaper. Select this entry by clicking on it. One can then use the colour palette button, which is the coloured block underneath the Desktop colours heading on the dialog, to change the background colour. Clicking the colour button will open a colour selection dialog, and adjusting the colour wheel will change the selected colour. Selecting OK will select that colour.
Changes made in the desktop background dialog will be applied instantly, so there is no need to press a button to save the changes.