function viewPic(img)
{    
   picfile = new Image();
   picfile.src =(img);
   fileCheck(img);
}

function fileCheck(img)
{    
   if( (picfile.width!=0) && (picfile.height!=0) )
   {
       makeWindow(img);
   }
   else
   {
       funzione="fileCheck('"+img+"')";
       intervallo=setTimeout(funzione,8);
   }
}

function makeWindow(img)
{    
   wd = picfile.width + 20;
   ht = picfile.height + 20;
   var args= "height=" + ht;
   args += ",width=" + wd;
   if (window.screen)
   {
       var avht = screen.availHeight - 30;
       var avwd = screen.availWidth - 10;
       var xcen = (avwd - wd) / 2;
       var ycen = (avht - ht) / 2;
       args += ",left=" + xcen + ",screenX=" + xcen;
       args += ",top=" + ycen + ",screenY=" + ycen + ",resizable=yes";    
   }
   return window.open(img, 'x', args);

}