win_png.htc

<public:component>
<public:attach event="onpropertychange" onevent="propertyChanged()" />
<script>

var supported = /MSIE (5\.5)|[6789]/.test(navigator.userAgent) && navigator.platform == "Win32";
var realSrc;
var blankSrc = "rien.gif";

if (supported) fixImage();

function propertyChanged() {
	if (!supported) return;

	var pName = event.propertyName;
	if (pName != "src") return;
	// if not set to blank
	if ( ! new RegExp(blankSrc).test(src))
		fixImage();
};

function fixImage() {
	// get src
	var src = element.src;

	// check for real change
	if (src == realSrc) {
		element.src = blankSrc;
		return;
	}

	if ( ! new RegExp(blankSrc).test(src)) {
		// backup old src
		realSrc = src;
	}

	// test for png
	if ( /\.png$/.test( realSrc.toLowerCase() ) ) {
		// set blank image
		element.src = blankSrc;
		// set filter
		element.runtimeStyle.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='" +
			src + "',sizingMethod='image')";
	}
}

</script>
</public:component>