Pixels

Pixels are the basic units of digital images and displays. A pixel, short for picture element, is the smallest addressable element in a raster image or on a digital screen. In color images, each pixel typically encodes red, green, and blue components that combine to form the final color and brightness seen by the viewer.

Images are structured as a grid of pixels with a defined resolution, expressed as width by height (for example, 1920 × 1080). The total number of pixels, or the image's pixel count, affects detail and file size. Each pixel’s color information is stored as bits; common formats use 24 bits per pixel (8 bits per channel) or 32 bits per pixel when an alpha channel is included.

Display devices render images by mapping each pixel to a physical element on the screen, which may be composed of subpixels (typically red, green, and blue). Subpixel geometry and dithering influence perceived sharpness and color, particularly at non-native resolutions. Scaling an image uses interpolation or filtering to estimate other pixel values, which can blur or introduce artifacts.

Pixels are central to raster graphics, where images are described by a fixed grid, in contrast to vector graphics, which describe shapes mathematically and render to pixels at display time. The term pixel originated as a contraction of picture element and has been in use since the 1960s.

Related terms include pixel density or pixels per inch, which describes how many pixels fit in a linear inch on a display, and color depth, which determines the number of distinct colors a pixel can represent.