Digital photographs are actually mosaics of millions of tiny squares called picture elements or just pixels. Like the impressionists who painted wonderful scenes with small dabs of paint, your computer and printer can use these tiny pixels to display or print photographs. To do so, the computer divides the screen or printed page into a grid of pixels. It then uses the values stored in the digital photograph to specify the brightness and color of each pixel in this grida form of painting by number
Sometimes a good example does what words will never do. So lets create an image of the letter a, going from the lowest possible resolution to something much larger than that. At a resolution of 1 by 1, (a square thats one dot by one dot), we end up with an image that looks like this
Well thats pretty boring. Why no letter V? There is no letter V because there are no more dots than the single dot we used. So lets bump up the resolution and go with a 10 by 10 square.
Alright. That looks like an V. Hopefully you can see whats going on here. The more we increase the resolution of the graphic, the clearer the v becomes. Now lets multiply the 10 by 10 resolution by 5 to get a 50 by 50 square.
Thats closer to what we want, but it still doesnt have that crisp quality Im used to seeing on my laptop. To get that, well need to increase the resolution even more. Lets multiply it by 2.
Thats better. Actually this image is at full resolution for the screen Im using to view it. That is to say, I cannot improve upon its quality because my laptop cannot display images at a higher resolution than that.