Pixels

What is pixels (PPI)? 

pixels 

A pixel is the smallest unit of a digital image that can be displayed and represented on a digital display device.

A pixel is the basic logical unit in digital graphics. Pixels are combined to form a complete image, video, pics or mobile phone screen and TV screen etc. 

Full information 

A pixel describes is some blend of three components of the color spectrum,  RGB. Up to three bytes of data are allocated for specifying a pixels color one byte for each major color component.

Screen image sharpness is sometimes expressed as PPI (pixels per inch). Pixel per inch is determined by both the physical screen size and the resolution setting. A given image will have lower resolution - fewer dots per inch - on a larger screen as the same data is spread out over a larger physical area. On the same size screen, the image will have lower resolution if the resolution setting is made lower - resetting from 800 by 600 pixels per horizontal and vertical line to 640 by 480 means fewer dots per inch on the screen and an image that is less sharp.

How pixels work and how to change pixel colors? 

Pixel is made up of three separate lights. Each of these is able to change in intensity, from none to full brightness. 
A signal is sent to every pixel with information about the brightness of each component part: Red, Green, and Blue. Our eye is sensitive to different wavelengths but creates all the colors we see through three main channels: Long, Medium, and Short wavelengths. The differing quantities of Red, Green, and Blue light emitted activates these receptors to create the sense of color we perceive.