title: PHP file_exists() can't check file existence when URL rewrite is enabled?
body: <p>in Zend FW:</p>
  
  <pre><code>file_exists('xx/xxx/xxxx.jpg');</code></pre>
  
  <p>returned 1, but xx/xxx/xxxx.jpg is not file or directory.</p>
  
  <p>it's an error page returned by Zend FW. because it's not a file or valid url</p>
  
  <p>how can I check file existence?</p>