many browsers "support" the PNG format, but not "fully". Many browsers for a
long time didn't support the "alpha channel" or transparency part, making
them not as usefull in terms of design (and its still pretty spotty at
best). Also PNGs can be saved at different bit depths ( 8, 24, 32 ) and not
all depths are supported in all browsers (ie the PNG will cause the browser
to crash or the image to display with the wrong colors). Although for some
older browsers, there are plug-ins available to view PNGs

I wish that they were more widely supported. PNGs are supposed to be able to
adjust for the differing gamma settings between platforms, so colors stay
consistent across platforms.

theres a list of supporting browsers here:
http://www.libpng.org/pub/png/pngapbr.html

~jacque

> > You mean I only imagined all the time that I went to www.gnu.org and
> > saw the graphics in Netscape 4.x?  (Of course, I just tried to verify
> > that and, although gnu.org is fine, www.gnu.org appears to be
> > unreachable from here...)
>
> No, it's not correct that Netscape must be >=6.0.
>
> The png link someone provided said that the BigTwo have had PNG
> display capability since around '97, and I just verified that Netscape
> 4.72 on SunOS at the U displays the little PNG title image I put on
> www.rephil.org.
>