[cclaerhout]

I understand ! Natch has updated his first version of his hack.

Here is the old one :

// PNG-24 Alpha Transparency with MSIE
/* ***
* replacePngTags - Justin Koivisto [W.A. Fisher Interactive] 7/1/2003 10:45AM
* function to IE display of PNG transparencies - integrated to vB3 by Natch@mobileforces.org
* *** */
function replacePngTags($x,$img_path='/forum/images/')
{
	$arr2=array();
	// make sure that we are only replacing for the Windows versions of Internet
	// Explorer 5+
	$msie='/msie\s([5-9])\.?[0-9]*.*(win)/i';
	if(!isset($_SERVER['HTTP_USER_AGENT']) ||
		!preg_match($msie,$_SERVER['HTTP_USER_AGENT']) ||
		preg_match('/opera/i',$_SERVER['HTTP_USER_AGENT']))
		return $x;

	// find all the png images in backgrounds
	preg_match_all('/background-image:\s*url\(\'(.*\.png)\'\);/Uis',$x,$background);
	for($i=0;$i<count($background[0]);$i++){
		// simply replace:
		//  "background-image: url('image.png');"
		// with:
		//  "filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(
		//      enabled=true, sizingMethod=scale src='image.png');"
		// haven't tested to see if background-repeat styles work...
		$x=str_replace($background[0][$i],'filter:progid:DXImageTransform.'.
			'Microsoft.AlphaImageLoader(enabled=true, sizingMethod=scale'.
			' src=\''.$background[1][$i].'\');',$x);
	}

	// OK, time to find all the IMG tags with ".png" in them
	$pattern='/<(input|img)[^>]*src=(\\\'|\\")([^>]*\.png)\2[^>]*>/i';
	preg_match_all($pattern,$x,$images);
	for($num_images=0;$num_images<count($images[0]);$num_images++){
		$original=$images[0][$num_images];
		$quote=$images[2][$num_images];
		$atts=''; $width=0; $height=0; $modified=$original;

		// If the size is defined by styles, find them
		preg_match_all(
			'/style=(\\\'|\\").*(\s?width:\s?([0-9]+(px|%));).*'.
			'(\s?height:\s?([0-9]+(px|%));).*\\1/Ui',
			$images[0][$num_images],$arr2);
		if(is_array($arr2) && count($arr2[0])){
			// size was defined by styles, get values
			$width=$arr2[3][0];
			$height=$arr2[6][0];

			// remove the width and height from the style
			$stripper=str_replace(' ','\s','/('.$arr2[2][0].'|'.$arr2[5][0].')/');
			// Also remove any empty style tags
			$modified=preg_replace(
				'`style='.$arr2[1][0].$arr2[1][0].'`i',
				'',
				preg_replace($stripper,'',$modified));
		}

		// size was not defined by styles, get values from attributes
		preg_match_all('/width=(\\\'|\\")?([0-9%]+)\\1/i',$images[0][$num_images],$arr2);
		if(is_array($arr2) && count($arr2[0])){
			$width=$arr2[2][0];
			if(is_numeric($width))
				$width.='px';

			// remove this from the tag
			$modified=str_replace($arr2[0][0],'',$modified);
		}
		preg_match_all('/height=(\\\'|\\")?([0-9%]+)\\1?/i',$images[0][$num_images],$arr2);
		if(is_array($arr2) && count($arr2[0])){
			$height=$arr2[2][0];
			if(is_numeric($height))
				$height.='px';

			// remove this from the tag
			$modified=str_replace($arr2[0][0],'',$modified);
		}

		// if either height or width were left out, son't replace this image this allows
		// the image to show up (not fixed) instead of not displaying the image at all
		if($width==0 || $height==0)
			continue;

		preg_match_all('/src=(\\\'|\\")([^\"]+\.png)\\1/i',$images[0][$num_images],$arr2);
		if(isset($arr2[2][0]) && !empty($arr2[1][0]))
			$image=$arr2[2][0];
		else
			$image=NULL;

		if(!empty($img_path)){
			// We do this so that we can put our spacer.png image in the same
			// directory as the image
			$tmp=split('[\\/]',$image);
			array_pop($tmp);
			$img_path=join('/',$tmp);
			if(strlen($img_path)) $img_path.='/';
		}

		// end quote is already supplied by originial src attribute
		$replace_src_with=$img_path.'spacer.png'.$quote.' style="width: '.$width.
			'; height: '.$height.'; filter: progid:DXImageTransform.'.
			'Microsoft.AlphaImageLoader(src=\''.$image.'\', sizingMethod='.
			'\'scale\');"';

		// now create the new tag from the old
		$new_tag=str_replace($image.$quote,$replace_src_with,
			str_replace('  ',' ',$modified));
		// now place the new tag into the content
		$x=str_replace($original,$new_tag,$x);
		$i++;
	}
	return $x;
}
// /PNG-24 Alpha Transparency with MSIE