Original description from 10 years ago:

"A lot of people ask things about pixel art, but most of them never really think about the most single essential point:

What is really a pixel ?

So I decide to draw this as a kind of learning image. A pixel is not really what it seems to be.
Pixels are like humans, they are affected by their environment. A CRT screen pixel is generically made of small red green and blue triplets arranged in a triangular mosaic. A TFT screen pixel is made of small packs of vertical red green and blue bars. A printer pixel is generally made of cyan magenta and yellow colors instead of red green and blue, and they often are of fixed intensity but various size.

A pixel really is more than a single dumb and meaningless point somewhere on the screen. A pixel is a world by itself and merit our loving attention, because without them all your crafted visual digital art would not exist at all."