title: file_exists() returns false, but the file DOES exist
body: <p>I'm having a very weird issue with file_exists(). I'm using this function to check if 2 different files in the same folders do exist. I've double-checked, they BOTH do exist.</p>
  
  <pre><code>echo $relative . $url['path'] . '/' . $path['filename'] . '.jpg';
  Result: ../../images/example/001-001.jpg
  
  echo $relative . $url['path'] . '/' . $path['filename'] . '.' . $path['extension'];
  Result: ../../images/example/001-001.PNG
  </code></pre>
  
  <p>Now let's use file_exists() on these:</p>
  
  <pre><code>var_dump(file_exists($relative . $url['path'] . '/' . $path['filename'] . '.jpg'));
  Result: bool(false)
  
  var_dump(file_exists($relative . $url['path'] . '/' . $path['filename'] . '.' . $path['extension']));
  Result: bool(true)
  </code></pre>
  
  <p>I don't get it - both of these files do exist. I'm running Windows, so it's not related to a case-sensitive issue. Safe Mode is off.</p>
  
  <p>What might be worth mentioning though is that the .png one is uploaded by a user via FTP, while the .jpg one is created using a script. But as far as I know, that shouldn't make a difference.</p>
  
  <p>Any tips?</p>
  
  <p>Thanks</p>