When I used PNG I became less popular than when I used GIF. LZW compression in GIF uses twice the storage as deflate compression in PNG. PNG is open source, GIF was unpatented in 2003. Both PNG and GIF show up in any browser released in 1999 or later. That's 7 yrs ago. Who uses IE4 or Netscape Communcator 4.7 anymore? I want to know.
IE 5.0+ supports transparent png
Okay everyone, I'll stop using PNG. I understand now. Animated PNG is actually be SWF (Macromedia Flash) because it supports PNG and JPG