So IEs PNG support is just fine?
Thank you for taking the time to contact us.
As you may be aware, Internet Explorer on Windows has had support for PNG images since version 4. A drawback in the current implementation has been support for per-pixel alpha values, which in no way detracts from PNG’s value as an alternative to other image formats. Based on feedback such as yours, we have provided a workaround for this issue.
Once again, thanks for providing feedback on Internet Explorer.
Lead Program Manager