In computer graphics, picture or graphic objects are presented as collection of discreet picture element called as "Pixel".

Pixel may be defined as small size object or colors spot that can be display on address on monitor.

Any image that is display on the monitor is made up of thousands of small pixels.

Each pixel has particular color and brightness value, those size of pixel depends on electron beam, they are very close and fine to each other to be perceptible by human eyes.