Pixel stands for picture element. It is the smallest visible element on a computer or TV screen and when they are assembled together, they make up an image. The more pixels that an image has, the more it can be enlarged without pixelation, (where the pixels become visible on the screen).
In the composite below, a section of the Empire State Building is enlarged as shown in the second photo, and in the third photo, we can actually see the pixels that make up the image. This is how an image is compiled – pixel by pixel. Notice in both composites, each pixel represents its respective color of the image.
In the image below, picture #1 is a photo of the High Line in Lower Manhattan. We enlarged a small section of the flowers as shown in picture #2. And in picture #3, we can see the square boxes which are the pixels.
In both composites, if we move backwards, we can see how the images are created as the pixels develop into shapes. The quality (how sharp the image will be displayed) depends upon the amount of pixels that the image has. The more pixels per image, the better the clarity of the image.