Pixel

The pixel is the basic unit of programmable color on a computer display or in a computer image
The address of a pixel corresponds to its physical coordinates.

In the below image shows the pixels approximate the actual image. The more closely the image resembles the original.

Bits per pixel

• The number of distinct colors that can be represented by a pixel depends on the number of bits per pixel (bpp). 
• A 1 bpp image uses 1-bit for each pixel. Each additional bit doubles the number of colors available, so a 2 bpp image can have 4 colors, and a 3 bpp image can have 8 colors:

Pixel representation

• 1 bpp, 21 = 2 colors (monochrome)
• 2 bpp, 22 = 4 colors
• 3 bpp, 23 = 8 colors

...

• 8 bpp, 28 = 256 colors
• 16 bpp, 216 = 65,536 colors
• 24 bpp, 224 = 16,777,216 colors

Usage of pixel

• Each pixel stores color information for your image. 
• The number of distinct colors that can be represented by a pixel depends on the amount of information stored for each pixel. 
• Information is stored as bits. 

Megapixel

• A megapixel (MP) is a million pixels 
• Single megapixel amounts to exactly one million pixels in an image.