PNG stands for "Portable Network Graphics". It was invented by a bunch of Internet fanatics
after the computer company Unisys had announced they were going to cash in on commercial
use of their LZH compression patent. In other words, it was invented as a free and open-source
successor to the GIF format. PNG supports true colors (GIF only supports 256 colors).

PNG is very suited for image editing. It is an extensible format for lossless, well-compressed
storage of raster images. It provides a relatively better replacement for GIF that's patent-free
and supports indexed-color, grayscale and an optional alpha channel. PNG works well in
applications of online viewing. PNG also provides full file integrity checking as well as simple
detection of common transmission errors and can store gamma and chromaticity data for
improved color matching on various platforms.