These are pictures and images used as a background on a computer screen, usually for the desktop of a graphical user interface. The term wallpaper is used by Microsoft Windows, while the Mac OS calls it a desktop picture. The common resolutions for the desktop wallpaper are 800x600, 1024x768, 1280x1024 and 1600x1200, however they are sometimes available in double-width versions (e.g. 2560×1024) for displaying on multi-monitor computers, where the image appears to fill two monitors. The most common file types are PNG and JPEG.
Typically, a wallpaper image may be centered, stretched, or tiled. When an image is centered, it is placed in the middle of the desktop and is surrounded by a solid color. When an image is stretched, it is stretched to cover all of the desktop. Only certain images can be stretched or they look distorted. An image that is tiled is placed on the desktop much like tiles are placed in a shower or a tiled floor. Tiling is commonly used for patterns instead of photos because a pattern is one square image that repeats itself across and down the screen, effectively forming a single image.
Photography is the process and art of recording pictures by means of capturing light on a light-sensitive medium, such as a film or an electronic sensor. Light patterns reflected or emitted from objects expose a sensitive silver halide based chemical or electronic medium during a timed exposure, usually through a photographic lens in a device known as a camera that also stores the resulting information chemically or electronically. Photography has many uses for business, science, art and pleasure.
The word "photography" comes from the French photographie which is based on the Greek (phos) "light" + (graphis) "stylus", "paintbrush" or (graphê) "representation by means of lines" or "drawing", together meaning "drawing with light." Traditionally, the product of photography has been called a photograph, commonly shortened to photo.