I'm a Linux user and don't have Windows installed, so I don't know much about IE. I recently tested a HTML page, that had transparent PNG graphics, with a friend's browser. She's using IE 6 and I was quite surprised to see that the transparent parts of my pictures weren't transparent. The PNG's were ok with Netscape 6 (both my Linux version and her Windows version), Mozilla, Opera and Konqueror. Only IE was having problems.
I refuse to believe that a recent version of IE can't handle transparent PNG's properly. Is this a problem with her browser only, or is IE really so poor that it still doesn't understand PNG?
No offence meant but the only guaranteed way to *really* test IE issues is to actually use IE to do the testing. That way I / client can be sure "IE Compatible" actually means IE compatible and not "Compatible with Opera pretending to be IE"...
On one of the PNG mail lists a while back this was discussed. Apparantly IE on the Macintosh has excellent support for PNG transparancy, both single-color and alpha channel. For reasons only the Bill can explain, Microsoft did not port this level of support to IE on Windows.