It's well known that Microsoft Internet Explorer 5.5 or 6.x - for Windows platform - cannot display PNG files with transparent backgrounds properly. ImageDraw controls solve this issue by implementing a well know PNG Hacking method based on the Internet Explorer AlphaImageLoader filter.

The EnablePngHack property of each ImageDraw controls is the responsible to accomplish the hacking when a PNG image must be rendered – the ImageFormat property is Png – and the Canvas fill is set with some transparency values.

In conclusion, PNG hacking is accomplished if the following things occur:

You can disable this feature setting the EnablePngHack property to false and implement your own PNG hacking method.