diff --git a/htdocs/core/filemanagerdol/connectors/php/connector.lib.php b/htdocs/core/filemanagerdol/connectors/php/connector.lib.php
index ca9a01bc37d..02bf537b9cf 100644
--- a/htdocs/core/filemanagerdol/connectors/php/connector.lib.php
+++ b/htdocs/core/filemanagerdol/connectors/php/connector.lib.php
@@ -954,10 +954,9 @@ function IsHtmlExtension($ext, $formExtensions)
 /**
  * Detect HTML in the first KB to prevent against potential security issue with
  * IE/Safari/Opera file type auto detection bug.
- * Returns true if file contain insecure HTML code at the beginning.
  *
  * @param string $filePath absolute path to file
- * @return boolean
+ * @return bool|-1		Returns true if the file contains insecure HTML code at the beginning, or -1 if error
  */
 function DetectHtml($filePath)
 {
@@ -1015,11 +1014,10 @@ function DetectHtml($filePath)
 /**
  * Check file content.
  * Currently this function validates only image files.
- * Returns false if file is invalid.
  *
  * @param 	string 	$filePath 		Absolute path to file
  * @param 	string 	$extension 		File extension
- * @return 	boolean					True or false
+ * @return 	bool|-1					Returns true if the file is valid, false if the file is invalid, -1 if error.
  */
 function IsImageValid($filePath, $extension)
 {