This is the best place I can think of to ask this.

Alright, so I've got an icon journal, just started it, going alright as far as I can see. Then my buddies tell me that they can't see most of my icons, and I figure out that apparently, IE does not like *.png files. Any clue on why this is? And if there's any way to remedy it, other than saving everything as evil *.jpg files? Any help would be appreciated. Thanks!