pixels, a minute area of illumination on a display screen, one of many from which an image is composed.
 image resolution,the detail an image holds. The term applies to raster digital images, film images, and other types of images. Higher resolutionmeans more image detail. Image resolution can be measured in various ways.
 megabyte, a unit of information equal to 2²⁰ bytes or, loosely, one million bytes.
megapixel,a unit of graphic resolution equivalent to one million or (strictly) 1,048,576 (2²⁰) pixels.
 gigabyte, a unit of information equal to one billion (10⁹) or, strictly, 2³⁰ bytes.
 jpeg,a format for compressing image files.
 psd, which stands for Photoshop Document, is the default format that Photoshop uses for saving data. PSD is a proprietary file that allows the user to work with the images' individual layers even after the file has been saved.
 white balance,the color balance on a digital camera.
 histogram, a diagram consisting of rectangles whose area is proportional to the frequency of a variable and whose width is equal to the class interval.
aperture,an opening, hole, or gap.
 shutter speed, the time for which a shutter is open at a given setting.
 depth of field, the distance between the nearest and the furthest objects that give an image judged to be in focus in a camera.
bitmap a representation in which each item corresponds to one or more bits of information, especially the information used to control the display of a computer screen.
, exposure, the state of being exposed to contact with something.
 watermarking,a faint design made in some paper during manufacture, which is visible when held against the light and typically identifies the maker.
 optical zoom, a true zoom feature. It allows you to zoom in (or out) on the subject in the LCD or viewfinder.
 digital zoom,  a function of a digital camera used to make the image seem more close-up. Digital zoom on a digital camera works the same as cropping and enlarging a photo in a graphics program.
 light meter, an instrument for measuring the intensity of light, used chiefly to show the correct exposure when taking a photograph.
 image stabilization,  a family of techniques used to reduce blurring associated with the motion of a camera or other imaging device during exposure.
 noise,random (not present in the object imaged) variation of brightness or color information in images, and is usually an aspect of electronic noise. It can be produced by the sensor and circuitry of a scanner or digital camera.
 lag time,the period of time between two closely related events, phenomena, etc., as between stimulus and response or between cause and effect: a time-lag between the declaration of war and full war production.
 hot shoe,a socket on a camera with direct electrical contacts for an attached flashgun or other accessory.
 fisheye,a wide-angle lens with a field of vision covering up to 180°, the scale being reduced toward the edges.
 macroa lens suitable for taking photographs unusually close to the subject.
, telephoto,a lens with a longer focal length than standard, giving a narrow field of view and a magnified image.
 wide angle,when speaking of cameras, refers to a low magnification lens that is able to direct a wide view of a scene to the camera's image sensor. What focal length lenses pass for wide angle depends on the size of the sensor used in the camera.
 DSLR.A digital single-lens reflex camera (also called a digital SLR or DSLR) is a digital camera combining the optics and the mechanisms of a single-lens reflex camera with a digital imaging sensor, as opposed to photographic film.