I never meant to become obsessive about getting PNG transparency working nicely in IE6. In the summer of 2003, I hit across a situation on a client project where what the designer wanted required the use of PNG transparency. The script that came to hand to get this working in IE6 at the time was called Sleight, but that only dealt with applying the filter to IMG elements. My design needed to do the same for CSS background images, so I hacked up a different version of the script for that purpose, called it bgSleight, and occasionally updated it.