diff --git a/inc/config.php b/inc/config.php
index 5fc38c8d..9a9de46c 100644
--- a/inc/config.php
+++ b/inc/config.php
@@ -2069,7 +2069,9 @@
     // Enable auto IP note generation of moderator deleted posts
     $config['autotagging'] = false;
 
-    // Enable PDF file thumbnail generation
+    // Enable PDF thumbnail generation.
+    // Requires a working installation of ghostscript and imagemagick.
+    // Imagemagick support of PDF files is not required.
     $config['pdf_file_thumbnail'] = false;
 
     // Enable TXT file thumbnail