The appearance of individual pixels or pixel blocks in a bitmapped image. For example, when an image is displayed or printed too large, the individual, square pixels are discernible to the naked eye, especially around the edges where one color or shade of gray meets another. See anti-aliasing and deinterlace.

Although images may be pixelated purposely for special effects as in the example below, pixelation is often due to some shortcoming. For example, when digital video is played, the decoder may not be able to keep up with the encoding rate, and the frames are pixelated. See videophile.