Have you tried the HTML equivalent?
<img src="http://www.mydomain.com/images/image.gif" alt="some description"/>
<img src="http://www.mydomain.com/images/image.gif" alt="some description"/>
headers_sent($filename, $linenum));
if (headers_sent($filename, $linenum)) {
echo "Headers already sent in $filename on line $linenum";
}
test === and I learn that === has the same meaning with ==.