Image

For images in Wikipedia, see Wikipedia:Images.

In common usage, an image (from Latin imago) or picture is an artifact 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, smiconductor storage chip, etc. In particular,
  • A core image (or core dump, from magnetic core memory, the predominant RAM technology of the 1960s) 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).
  • A ROM image is a copy of the contents of an entire ROM chip, typically a video game executable, which may then be stored on another medium (in the case of copyrighted games, this comes under the category of software piracy).
• In mathematics, an image of a function consist of the output values of the mathematical function.
• 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, although these terms have very specialised meanings within certain sects and should not be held as always synonymous.
• In social psychology an image is a representation.
• Image Comics is an American publisher of comic books.
• Body image
• The IMAGE spacecraft currently observing the Earth's magnetosphere

See also

• optics
• imaging, photography, and digital imaging
• image processing
• digital camera
• graphical output device
• Wikipedia:Featured pictures
• Wikipedia:Image use policy
• Wikipedia:Image requests
• Wikimedia Commons free multimedia repository, that you can use directly in Wikipedia. You can upload new images or use the stored ones.
• Wikipedia:Extended image syntax (how to include images in Wikipedia pages).
• Category:Wikipedia image help pages (http://www.wikipedia.org/wiki/Category:Wikipedia_image_help).

External links

• "Chance Image" at The Dictionary of the History of Ideas (http://etext.lib.virginia.edu/cgi-local/DHI/dhi.cgi?id=dv1-47)
• Ithaki: Web search engine for images (http://images.ithaki.net)
• Irfanview 3.95: Free image viewing software (http://ejrs.com/irfanview)de:Bild

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