Lately I've seen alot of image files with the ending .png and I'm confused. What is a png file? I've heard of gifs, jpgs, bmps, art but not any png. Anybody want to clear things up by telling me where this kind of file was invented and what it does?

.PNG (meaning portable network graphic) is an officially endorsed "W3C recommendation" image format that allows upto 64bit (RGBA - one channel more than jpeg) per pixel information with lossless compression. (though as yet Internet Explorer cannot properly render alpha channel transparency, though does try. Moz(gecko) can of course).

Developed by Greg Roelofs, .PNG also has two brothers (.MNG - which support animation and .JNG - which uses a lossy compression algorythm like jpeg)

Further reading:
Story of PNG - by Greg Roelofs (http://www.libpng.org/pub/png/slashpng-1999.html)
Brief W3C notes (http://www.w3.org/Graphics/PNG/)

Since unisys started charging for use of their LZW compression algorythm (used in .gif and .tiff etc), open-sourced projects have dropped .gif support almost entirely - eg GD libraries for PHP. Moving to use .PNG is a much better option.

Thanks!