A pixel(or picture element) is the smallest item of information in an image. Pixels are basically arranged in a 2-dimensional grid that represents using squares. Each pixel is a sample of an original image, where more samples typically provide more-accurate representations of the original. The intensity of each pixel is variable; in color systems, each pixel has typically three or four components such as red, green, and blue, or cyan, magenta, yellow, and black.
Pixelation is the term used in computer graphics to describe blurry sections or fuzziness in an image due to visibility of single-colored square display elements or individual pixels. It mostly occurs with non-vector or raster-based images or with images which are resolution dependent due to the number of pixels per inch of the image being low. For a good quality image, pixelation must be avoided or minimized.
