Use window.open in a window with custom background

I need help putting a background into the window that opens a player on my site. Here is the code I'm using. The way I put the path of the background image, it is not appearing. Can anyone help me?

 <script language="JavaScript">
  function abrir(URL) {

  var width = 400;
  var height = 50;

  var left = 750;
  var top = 199;

  window.open(URL,'/site107fm/bgjanelaaovivo/bgradioshow.png','janela', 
  'width='+width+', height='+height+', top='+top+', left='+left+', 
  scrollbars=yes, status=no, toolbar=no, location=no, directories=no, 
  menubar=no, resizable=no, fullscreen=no,');

  }
  </script>