Today, I put a PNG transparency hack into use. For those of you with social lives, this is one of several PNG transparency fixes out there that blesses Internet Explorer 6 (and even IE5.5) with support for PNG32 images. Basically, utilizing one of these hacks will allow your older browser to show multiple levels of transparency instead of the more widely supported yes or no transparency. Newer versions of IE (IE7+) support PNG32 natively.
The method of the day was IE PNG Fix 1.0 from TwinHelix. It was extremely easy to implement, and only requires adding a line to your CSS. The ZIP package contains an HTML file that explains installation and use.
There’s one caveat I’d like to point out. No matter how tempting it is because it reminds you of the old single pixel spacer days, don’t delete the blank.gif image that is part of the installation. It’s there for a reason. Deleting or having blank.gif in the wrong folder will cause IE6′s red X and alt tag to display over what is otherwise the desired behavior. You’ll notice that that hack works, but without that GIF, your page gets red X measels.
See also PNG32 hacks and IE6. Is it worth it?