Picture Element (Pixel)
The area of the smallest element of a picture that can be distinguished from its neighboring elements. Pixels per inch (PPI) is a measurement of the pixel density (resolution).
For example, 300 x 300 PPI indicates that there are 300 pixels per inch both in the horizontal and vertical directions, or in other words, there are 90,000 pixels (300 x 300) per square inch. More pixels indicate richer colors and better color reproduction.
