Image in Table List (Works in Firefox but not in IE)

[eluser]cinewbie81[/eluser]
Hi guys,

Table List php file

Code:

$htmlCode = '';
$htmlCode = '<td align=left.'> <span class="'.'warning'.'"></span></td>';
echo $htmlCode

Css file

Code:

span.warning
{
    padding-left:20px;
    background: transparent url(../images/warning.gif) no-repeat left;
}

The code above will display warning.gif icon in the table list for Firefox, but it display nothing in IE. Any idea ?

Thanks.