Pixel resolution refers to the total number of pixels in a given digital image. A pixel is the smallest piece of an image as it is displayed. It can be thought of as a dot.
Each pixel can be illuminated and colored individually and together they form the digital images seen on a computer screen or a digital photograph. Pixel resolution is typically given as a pair of numbers, such as 640 x 480. The first number indicates the number of pixels being displayed horizontally and the second number indicates the number of pixels being displayed vertically. Higher resolutions produce sharper images with more detail. The higher the numbers, the higher the resolution.