diff --git a/core/lib/Drupal/Core/Image/Image.php b/core/lib/Drupal/Core/Image/Image.php
index b446cd3..6b56ccc 100644
--- a/core/lib/Drupal/Core/Image/Image.php
+++ b/core/lib/Drupal/Core/Image/Image.php
@@ -158,7 +158,7 @@ public function getType() {
    */
   public function getMimeType() {
     $this->processInfo();
-    return image_type_to_mime_type($this->type, FALSE);
+    return image_type_to_mime_type($this->type);
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Image/ImageInterface.php b/core/lib/Drupal/Core/Image/ImageInterface.php
index 47aaf22..59f3be8 100644
--- a/core/lib/Drupal/Core/Image/ImageInterface.php
+++ b/core/lib/Drupal/Core/Image/ImageInterface.php
@@ -32,7 +32,7 @@ public function isExisting();
    * Returns the default file extension of the image, based on its type.
    *
    * @return string
-   *   The extension of the file, or an empty string if the image is invalid.
+   *   The default file extension of the image.
    */
   public function getDefaultExtension();
 
@@ -93,7 +93,7 @@ public function getType();
    * Returns the MIME type of the image file.
    *
    * @return string
-   *   The MIME type of the file, or an empty string if the file is invalid.
+   *   The MIME type of the image file.
    */
   public function getMimeType();