Pixel as an elementary element of a digital image

A pixel is the basic unit of digital raster graphics, representing a single illuminated point on a monitor.

Definition of Pixel

A pixel (from the English term "picture element"), abbreviated as px or pel, is the fundamental unit of digital (bitmap) graphics. It is a physical point, the smallest addressable element on a monitor—a single point of a digital or printed image.

The points on the screen form a square grid, and each pixel can be uniquely identified by its coordinates. Due to the limited number of pixels and the finite refresh rate of the display, many undesired effects can occur when rendering on a monitor. Common issues include aliasing, moiré, image blurriness, mosaic distortion, and loss of information during resizing, enlarging, and rotating of images.

Pixel Size

The size of a pixel is influenced by the type of monitor. For conventional analog types, pixel size changes with resolution adjustments. LCD screens typically have a fixed number of physical pixels (known as native resolution) tied to the resolution used (e.g., 1024×768), and displaying a single resolution on such a monitor can lead to some image distortion. However, common resolutions today include 1366×768px, 1920×1080px, and 4096×2160px, referred to as 4K. There are also displays available with 8K resolution, which means 7680×4320px.