Image
From Halbeeg, the open encyclopedia · Af-Soomaali
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An image is a two-dimensional representation of a thing, place, or idea. It may be made by hand, such as through drawing or painting, or created with a device such as a camera. The primary purpose is to show to the eye something that is not physically present, so that people can obtain information from it or enjoy it.
The word 'image' is used with several meanings. In technical contexts, it refers to visual data that can be stored on paper or a computer. In everyday speech, it is used more broadly—for instance, when one says that a person or group has a certain 'image', meaning how people perceive them.
How images are made
The earliest images were made by hand: marks scratched on stone, pigment drawing, and pictures in handwritten books. In later centuries, photography was developed, which captures light reflected from an object onto a chemically treated surface, from which the image emerges. Today's digital cameras convert light into electronic data, which is stored as a file.
Digital images
A digital image typically consists of a grid of small dots called pixels. Each pixel has a color value. The number of pixels in an image is referred to as its resolution—the higher the resolution, the more detail appears, but the file becomes larger. There also exist images based on geometric forms (vector images), which can be scaled without loss of quality.
Mathematical and technical concepts
In mathematics, the term 'image' has a specific meaning: it is the result of a function applied to a given input. If a function f maps an input x to an output y, then y is called the image of x. Similarly, in optics, an image is the point where light rays converge after passing through a mirror or lens; it may be real and visible on a screen, or virtual and visible only to the eye.
Public use
Images are used in education, medicine (such as diagnosis and other clinical purposes), journalism, art, and historical documentation. Because an image is understood quickly, it can be an effective tool for communicating information to people. For this reason, images can also be used to persuade or mislead audiences, particularly when parts are removed or altered by software.