PNG
Definition:
PNG stands for Portable Network Graphics and represents a file format used to store graphics and images. PNG is a successor to the GIF image format in that it is not limited to 256 colors. However, images stored in the PNG format can not be animated as they can with the GIF format.
Here's a word you may not know...
BitTorrent
BitTorrent is a peer-to-peer protocol that allows computers to distribute files. Unlike other file sharing protocols, BitTorrent relies on multiple computers to share tiny pieces of each file. Therefore no one computer has the burden of having to distribute the entire file.
BitTorrent networks are used widely to distribute large music and video files.