Pixel is like little square, each little square has its color. Composing all the little square together, there comes to a picture. So once you magnify the picture 100 times, there you will see the mosaic effect picture, the little square means one color, also means “one pixel”. Take for instance, 1 million pixels mean the picture is composed by 1 million little squares; 4 million pixels means 400 million little squares. The more the pixels, the better picture quality, the better resolution, and picture would be more refined. Thus, the size of the picture can be magnified even bigger.