Что-то вроде такого
require_once("/getid3/getid3.php");
$Path=$song."Name.mp3";
$getID3 = new getID3;
$OldThisFileInfo = $getID3->analyze($Path);
if(isset($OldThisFileInfo['comments']['picture'][0]))
{
header('Content-Type: ' . $OldThisFileInfo['comments']['picture'][0]['image_mime']);
echo $OldThisFileInfo['comments']['picture'][0]['data'];
die;
}