pixel

A Closer Look: The images on a computer screen are composed of tiny dots called pixels (short for picture element). The computer controls each pixel individually. Most monitors have hundreds of thousands, or often millions, of pixels that are lit or dimmed to create an image. Each pixel of a color screen is made out of one red, one blue, and one green subpixel, generally arranged in a triangle, adjusted individually to create the combined effect of a single color but treated as a unit pixel for determining resolution. Pixels vary in size according to the size and resolution of the monitor. Smaller pixels provide higher resolution, and therefore sharper images, but require more memory to store the color and intensity data of each pixel and more processing time to refresh the screen. Resolution is frequently referred to in terms of dpi, or dots per inch.