introduction to computer graphics pixels key concept for all computer graphics systems is the pixel pixel was originally word formed from combining and shortening the words picture (or pixand element pixel is cell on the computer screen each cell represents dot on the screen the size of this dot or cell and the number of cells available will vary depending upon the typesize and resolution of the screen for exampleit was common for early windows pcs to have by resolution display (using vga graphics cardthis relates to the number of pixels in terms of the width and height this meant that there were pixels across the screen with rows of pixels down the screen by contrast todays tv displays have by pixels the size and number of pixels available affects the quality of the image as presented to user with lower resolution displays (with fewer individual pixelsthe image may appear blocky or poorly definedwhere as with higher resolution it may appear sharp and clear each pixel can be referenced by its location in the display grid by filling pixels on the screen with different colours various images/displays can be created for examplein the following picture single pixel has been filled at position by sequence of pixels can form linea circle or any number of different shapes howeversince the grid of pixels is based on individual pointsa diagonal line or circle may need to utilise multiple pixels which when zoomed may have jagged edges for examplethe following picture shows part of circle on which we have zoomed in