The terms desktop wallpaper, desktop picture and desktop background all refer to an image used as a background on a computer screen. "Wallpaper" is the term used in Microsoft Windows, while Mac OS X calls it a "desktop picture".
The first use of a wallpaper in combination with overlapping windows was in the experimental office system, Officetalk, developed by Xerox in 1975. The model used in Officetalk produced a 25% gray, using dots two pixels high to avoid flicker on the screen.
Many standard screen resolutions are proportional in a 4:3 ratio, so an image scaled to fit in a different-sized screen will still be the right shape, keep in mind that scaling may impact the image quality. Common desktop wallpaper resolutions are: 800x600, 1024x768, 1280x1024 and 1600x1200.
Users with widescreen (16:9 or 16:10) monitors have different aspect ratio requirements for wallpaper, and can often be cropped to the correct shape without loss of quality.
The common formats are PNG and JPEG. Some Mac OS and other operating systems support vector wallpapers. This format has the advantage in that one file can be used for any screen size without loss of quality.
If you do not desire a picture for your desktop wallpaper, many systems are capable of using a single color as the background.
Desktop wallpapers are a great way to add some inspiration and style to an office. In the month of May Google recorded a 1,220,000 global monthly search volume. Did I mention they are popular?