thumb|The act of making a 2D image with a [[mobile phone camera. The display of the phone shows the photograph that will be made and stored.|right]]
An image or picture is a visual representation. An image can be two-dimensional, such as a drawing, painting, or photograph, or three-dimensional, such as a carving or sculpture. Images may be displayed through other media, including a projection on a surface, activation of electronic signals, or digital displays; they can also be reproduced through mechanical means, such as photography, printmaking, or photocopying. Images can also be animated through digital or physical processes.
In the context of signal processing, an image is a distributed amplitude of color(s). In optics, the term image (or optical image) refers specifically to the reproduction of an object formed by light waves coming from the object.
A volatile image exists or is perceived only for a short period. This may be a reflection of an object by a mirror, a projection of a camera obscura, or a scene displayed on a cathode-ray tube. A fixed image, also called a hard copy, is one that has been recorded on a material object, such as paper or textile.
A single image may exist in all three categories at the same time. The Statue of Liberty provides an example. While there have been countless two-dimensional and three-dimensional "reproductions" of the statue (i.e., "icons" themselves), the statue itself exists as
- an "icon" by virtue of its resemblance to a human woman (or, more specifically, previous representations of the Roman goddess Libertas or the female model used by the artist Frederic-Auguste Bartholdi).
- an "index" representing New York City or the United States of America in general due to its placement in New York Harbor, or with "immigration" from its proximity to the immigration center at Ellis Island.
- a "symbol" as a visualization of the abstract concept of "liberty" or "freedom" or even "opportunity" or "diversity".
Critiques of imagery
The nature of images, whether three-dimensional or two-dimensional, created for a specific purpose or only for aesthetic pleasure, has continued to provoke questions and even condemnation at different times and places. In his dialogue, The Republic, the Greek philosopher Plato described our apparent reality as a copy of a higher order of universal forms. As copies of a higher reality, the things we perceive in the world, tangible or abstract, are inevitably imperfect. Book 7 of The Republic offers Plato's "Allegory of the Cave," where ordinary human life is compared to being a prisoner in a darkened cave who believes that shadows projected onto the cave's wall comprise actual reality. Since art is itself an imitation, it is a copy of that copy and all the more imperfect. Artistic images, then, not only misdirect human reason away from understanding the higher forms of true reality, but in imitating the bad behaviors of humans in depictions of the gods, they can corrupt individuals and society.
Echoes of such criticism have persisted across time, accelerating as image-making technologies have developed and expanded immensely since the invention of the daguerreotype and other photographic processes in the mid-19th century. By the late 20th century, works like John Berger's Ways of Seeing and Susan Sontag's On Photography questioned the hidden assumptions of power, race, sex, and class encoded in even realistic images, and how those assumptions and such images may implicate the viewer in the voyeuristic position of a (usually) male viewer. The documentary film scholar Bill Nichols has also studied how apparently "objective" photographs and films still encode assumptions about their subjects.
Images perpetuated in public education, media, and popular culture have a profound impact on the formation of such mental images:
Religious critiques
Despite, or perhaps because of, the widespread use of religious and spiritual imagery worldwide, the making of images and the depiction of gods or religious subjects has been subject to criticism, censorship, and criminal penalties. The Abrahamic religions (Judaism, Christianity, and Islam) all have had admonitions against the making of images, even though the extent of that proscription has varied with time, place, and sect or denomination of a given religion. In Judaism, one of the Ten Commandments given by God to Moses on Mount Sinai forbids the making of "any graven image, or any likeness [of any thing] that [is] in heaven above, or that [is] in the earth beneath, or that [is] in the water under earth." In Christian history, periods of iconoclasm (the destruction of images, especially those with religious meanings or connotations) have broken out from time to time, and some sects and denominations have rejected or severely limited the use of religious imagery. Islam tends to discourage religious depictions, sometimes quite rigorously, and often extends that to other forms of realistic imagery, favoring calligraphy or geometric designs instead. Depending on time and place, photographs and broadcast images in Islamic societies may be less subject to outright prohibition. In any religion, restrictions on image-making are especially targeted to avoid depictions of "false gods" in the form of idols. In recent years, militant extremist groups such as the Taliban and ISIS have destroyed centuries-old artifacts, especially those associated with other religions.
In culture
Virtually all cultures have produced images and applied different meanings or applications to them. The loss of knowledge about the context and connection of an image to its object is likely to result in different perceptions and interpretations of the image and even of the original object itself.
Through human history, one dominant form of imagery has been in relation to religion and spirituality. Such images, whether in the form of idols that are objects of worship or that represent some other spiritual state or quality, have a different status as artifacts when copies of such images sever links to the spiritual or supernatural. The German philosopher and essayist Walter Benjamin brought particular attention to this point in his 1935 essay "The Work of Art in the Age of Mechanical Reproduction."
Benjamin argues that the mechanical reproduction of images, which had accelerated through photographic processes in the previous one hundred years or so, inevitably degrades the "authenticity" or quasi-religious "aura" of the original object. One example is Leonardo da Vinci's Mona Lisa, originally painted as a portrait, but much later, with its display as an art object, it developed a "cult" value as an example of artistic beauty. Following years of various reproductions of the painting, the portrait's "cult" status has little to do with its original subject or the artistry. It has become famous for being famous, while at the same time, its recognizability has made it a subject to be copied, manipulated, satirized, or otherwise altered in forms ranging from Marcel Duchamp's L.H.O.O.Q. to Andy Warhol's multiple silk-screened reproductions of the image.
In modern times, the development of "non-fungible tokens" (NFTs) has been touted as an attempt to create "authentic" or "unique" images that have a monetary value, existing only in digital format. This assumption has been widely debated.
Other considerations
The development of synthetic acoustic technologies and the creation of sound art have led to considering the possibilities of a sound-image made up of irreducible phonic substance beyond linguistic or musicological analysis.
Still or moving
thumb|2D [[pencil drawing image|alt=Picture, Image]]
A ' is a single static image. This phrase is used in photography, visual media, and the computer industry to emphasize that one is not talking about movies, or in very precise or pedantic technical writing such as a standard.
A ' is typically a movie (film) or video, including digital video. It could also be an animated display, such as a zoetrope.
A still frame is a still image derived from one frame of a moving one. In contrast, a film still is a photograph taken on the set of a movie or television program during production, used for promotional purposes.
In image processing, a picture function is a mathematical representation of a two-dimensional image as a function of two spatial variables. The function f(x,y) describes the intensity of the point at coordinates (x,y).
Literature
In literature, a "mental image" may be developed through words and phrases to which the senses respond. It involves picturing an image mentally, also called imagining, hence imagery. It can both be figurative and literal.