Find out what a pixel is.
A pixel (pix [for picture] element) is the smallest element on a video display screen. A screen contains thousands of pixels, each of which can be made up of one or more dots or a cluster of dots. On a simple monochrome screen, a pixel is one dot; the two colors of image and background are created when the pixel is switched either on or off. Some monochrome screen pixels can be energized to create different light intensities to allow a range of shades from light to dark. On color screens, three dot colors are included in each pixel - red, green, and blue. The simplest screens have just one dot of each color, but more elaborate screens have pixels with clusters of each color. These more elaborate displays can show a large number of colors and intensities. For one color screens, black is created by leaving all three colors off; white by all three colors on; and a range of grays by equal intensities of all the colors.
The most economical displays are monochrome, with one bit per pixel, with settings limited to on and off. High-resolution color screens, which can use a million pixels, with each color dot using four bytes of memory, would need to reserve many megabytes just to display the image.