The cell is nature's building block, and the pixel is the web designer's. Pixel is one of those half-baked half-acronyms:PICture ELement. It refers to how monitors divide the display screen into thousands or millions of individual dots. A pixel is one of those dots. An 8-bit color monitor can display 256 pixels, while a 24-bit color monitor can display more than 16 million. If you design a web graphic on a 24-bit monitor, there's an excellent chance that many of your 16 million pixels won't be seen by visitors to your site. Since the agreed-upon lowest common denominator palette for the web has 216 colors, you should design your graphics using 8-bit color.
(see Bit Depth)
