title: Uploaded images in Drupal are being automatically deleted
body: <p>I am new to Drupal and have a small problem. When I upload an image using below code, the image is saved successfully. But after some time the image is automatically deleted. So far I have been unable to find the problem.</p>
  
  <p>My code is:</p>
  
  <pre><code>file_prepare_directory($_filePath, FILE_CREATE_DIRECTORY); 
  $file = file_save_upload('thumb_img', '', $_filePath);
  </code></pre>
  
  <p>Thanks.</p>