I'm using this code to check if a variable has a value and then do one of two things

PHP Code:
 if(isset($pic)) { 
    echo(
"<a href="edit_composer.php?id=$id" class=\"alt\"><img src="composers/$pic" alt=\"picture\" border=\"0\"></img></a><br />");
  } else {
  echo(
"<a href="edit_composer.php?id=$id" class=\"alt\"><img src=""\"composers/photonotavailable.gif\" alt=\"picture\" border=\"0\"></img></a><br />");
  } 
The variable $pic is coming from a database query. If a value is there the picture gets displayed, but if there is no value ($pic is empty) the "photonotavailable.gif" is NOT displayed. If I view the source in such a case, I see the relevant line is
<img src="composers/" alt="picture" border="0"></img>
I don't see the problem. Help? Thanks.