Transparent PNG Support
We get a lot (and I do mean a lot) of complaints about the lack of alpha channel support for PNG in Internet Explorer. Quite right too! This is an optional part of the PNG specification but it is the part that actually makes PNG more useful that other image formats. I am hopeful that we may be able to address this at some point in the future but at this stage we can't say exactly when or offer any guarantees. If anyone does offer you a guarantee about a feature shipping in a future piece of software then you should be very suspicious.
Unfortunately we can't turn back time and add this functionality. Or maybe we can!
There are workarounds that make use of the AlphaImageLoader filter supplied with Internet Explorer. Now using this filter in its raw form involves adding script to the page. I know many web designers are uncomfortable with adding script as it also can make supporting these web pages more difficult particularly if they don't have a programmer to turn to when things stop working. Fortunately a few clever people have wrapped up the functionality in a component known as a behavior so all a web designer needs to do is add a style for images to their page
img { behavior: url("pngbehavior.htc");}
and place the pngbehavior.htc file with the page on their server.
See http://webfx.eae.net/dhtml/pngbehavior/pngbehavior.html and http://www.mongus.net/pngInfo/ for a couple of complete samples and tutorials on how to do this.
I'm certainly not pretending that this is as good as native support for transparent PNG, and I can assure you we haveheard the requests to support this and are taking the feedback seriously. However I do think this solution offers a good way to allow designers to use these effects today to build some exceptionally beautiful pages.
