title: Warning: chmod(): Can not call chmod() for a non-standard stream
body: <p>I am trying to change file permission to 0777 in php but I get this error: 
  <code>Warning: chmod(): Can not call chmod() for a non-standard stream</code>
  I tried with <code>chmod</code> but doesn't work.</p>
  
  <pre><code>$imagethumb = 'http://'.$root.'/scrapers/thumbnails/'.$copiedimage;
      //looks like http://domain.com/scrapers/thumbnails/image.jpeg
  chmod($imagethumb, 0777);
  </code></pre>
  
  <p>Please let me know where I am mistaking.</p>