Inserting thumbs with rel tag?

function selectURL(thumb,pop)
         {   
              window.parent.close();
              window.parent.opener.CKEDITOR.tools.callFunction(<?php echo $_GET['CKEditorFuncNum'] ?>, thumb);

               // im trying this
               window.opener.document.getElementById("167_textInput").value = pop; 

      return false;
           }

<a href="Path to POP" rel="modal"><img src="Path to THUMB" /></a>