Image

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In common usage, an image (from Latin imago) or picture is an artefact that reproduces the likeness of some subject -- usually a physical object or a person.

Images may be two-dimensional (e.g. a photograph) or three dimensional (e.g. a statue). They are typically produced by optical devices -- such as a cameras, mirrors, lenses, telescopes, microscopes, etc. and natural objects and phenomena, such as the human eye or water surfaces.

The word image is also used in the broader sense of any two-dimensional figure or illustration, e.g. a map, a graph, a pie chart, an abstract painting, etc. In this wider sense, images can also be produced manually (by drawing, painting, carving, etc.), by computer graphics technology, or a combination of the two (see pseudo-photograph).

A volatile image is one that exists only for a short period of time, e.g. the reflection of an object by a mirror, a projection of the sun on a wall by a pinhole camera, or a scene displayed on a cathode ray tube. A fixed image, also called hardcopy, is one that has been recorded on a material object, such as paper or textile.

A mental image exists in someone's mind: something one remembers or imagines. The subject of an image need not be real; it may be an abstract concept, such as a graph or function -- or an imaginary entity or being.

Specialized meanings

The word also has many specialized meanings in various disciplines and contexts:

In geometric optics, a lens can produce a real image or a virtual image.
In many other scientific and technical contexts, image usually means a two-dimensional signal -- a physical phenomenon that can be modeled as a function from a two-dimensional domain (such as the plane or a rectangle) to some set of values, usually real numbers or vectors. This sense covers not only digital images but also analog ones, such as photographs. See image processing.
In computer graphics and digital image processing, the word image almost always means digital image or, by extension, any computer description of an image, e.g. a raster map, an image file, or a 2D computer graphics model. For embedding an image in a webpage, see HTML element#Images.
In computer science the word image can also mean an exact (bit-by-bit) copy of the contents of some device, such as a hard disk, floppy disk, CD-ROM, etc.. In particular,
- A core image (or core dump) is a faithful copy of the data stored in the main memory of a computer or process.
- An executable image is a structured file containing machine instructions and data, which can be loaded into a process's virtual memory and executed. See kernel (computers).
In mathematics, an image is a value or set of values of a function. Specifically, let f be a function from the set X to the set Y. If a is an element of X, then its image under f is the value f(a). If A is a subset of X, then its image under f is f(A) = {f(a) : a∈A}. Finally, the image of f itself is f(X), i.e. the same as the range of f.
In finance, the image is a coefficient (stock image) that bridges a stock's fundamental value and its market price.
In philosophy, an image is a conception or idea.
In religion, an image is an idol or icon.
In social psychology an image is a representation.

Also Image Comics is an Americann publisher of comic books.

Image

Specialized meanings

See also