The terms wallpaper, desktop picture and desktop background refer to an image used as a background on a computer screen, usually for the desktop of a graphical user interface. Many screen resolutions are proportional in a 4:3 ratio, so an image scaled to fit in a different-sized screen will still be the correct shape, although that scaling may impact quality. Common wallpaper resolutions are connected to common desktop resolutions: 800×600, 1024×768, 1280×1024 and 1600×1200.

Most display systems are capable of specifying a single colour to use as the background in place of wallpaper, and some (such as KDE or GNOME) allow colour-gradients to be specified. Early versions of Mac OS and Microsoft Windows allowed for small repeating patterns to tile the desktop.

Desktop backgrounds that are used usually fall into one of the following categories: automobiles, models and celebrities, scenery, abstract art, movies, pets, family, symmetry, and personal photos. It is common to corporate logos or plain backgrounds on business computers, as such guidelines that are often specified by the company.

Some operating environments (e.g. KDE, Mac OS X, and Windows 7) allow a number of different desktop backgrounds to be used, and changed from a set of selected images to display different backgrounds at different times. In environments where this is not possible off-hand, third-party tools may be able to have this be done.

To create nice desktop backgrounds, Adobe Flash can be used. By using this tool, dynamic or interactive backgrounds can be designed. Microsoft Windows 98 through XP allowed WebPages to be set as frames on the desktop which may be dynamic pages. Microsoft Windows Vista Ultimate also has the ability to use a video as a desktop background. Users can choose to use their own home videos which loop continuously, or use one already installed.

Some media players, like VLC, can redirect video playback to the desktop, allowing any video to be used as a background. Programs such as Xplanet and EarthDesk use Internet connections and graphics calculations to change the desktop background with real data, such as a shadowed view of the earth, the latest cloud or weather map, or various events.

Desktop backgrounds, in general, aid in the user’s creative mind’s workshop. It is a tool that can make a difference in the individual’s attitude and behaviour. Creating a background that caters to a person’s needs helps in encouraging his or her work environment and also in the personal life.

Desktop themes are available in the internet for all the operating systems for free. The users also can create their own desktop backgrounds or themes. Microsoft used to require that users purchase an application called Microsoft Plus! to use desktop themes, but they included it as standard issue in Windows 98 and Windows Me. The initial release of Windows 2000 does not include the Plus! package (or its equivalent), although high customer demand leads some industry watchers to predict that the Plus! package will either be included in the next edition of Windows 2000, or be released separately (as it was for Windows 95). In Linux, the latest version of the KDE graphical desktop environment includes a tool to enable users to change their desktop theme.

In computing, a theme is a preset package containing graphical appearance details, used to customize the look and feel of (typically) an operating system, widget set or window manager. Graphics themes for individual applications are often referred to as skins and the words are often used equivalently, the primary difference being one of scope.

Themes are often used to change the appearance of a wide range of things at once, which makes them much less granular than allowing the user to set each option individually. For example, one might want the window-borders from a particular theme, but installing it would also alter the desktop themes. One method for dealing with this is to allow the user to select which parts of the theme they want to load, for example in Windows 98, you could load the background and screensaver from a theme, but leave the icons and sounds untouched.

Desktop themes are important in lot of ways. They generally add colour and zest to any desktop. Since, desktop themes are more to do with the individual’s taste and likes, desktop themes aid in boosting the morale of the person in more ways than one.