Hello My Problem "transparent png" and "alpha(opacity=50)"

Problem This...


Please Help me ...

Code This
HTML Code:
<style type="text/css">
#alImg1 img {
	filter:progid:DXImageTransform.Microsoft.Alpha(opacity=50);
}
#alImg1, #alImg2 {
	display: inline-block;
}
body {
	background-image: url(line.png);
}
</style>
<span id="alImg1" > 
	<img src="transparentBorder.png" width="227" height="226" border="0" alt=""></span>
<span >
<img src="transparentBorder.png" width="227" height="226" border="0" alt=""></span>