use pngs instead of gifs in geeklog distribution

that shuts out a portion of the users/viewers who use a lower-end windows machine - I know the ones here at school require you to download the quicktime plugin if you want to view a png - and that\'s just a normal windows 98 machine.

Personally, I\'d say png all the way - but if anything, it should be optional - that is, two sets of icons which are specifiable in config.php of which to use... you know, like a $icon_extension = \'.gif\'; or something.