diff --git a/core/modules/image/image.api.php b/core/modules/image/image.api.php
index 06e681b..5ebd416 100644
--- a/core/modules/image/image.api.php
+++ b/core/modules/image/image.api.php
@@ -46,11 +46,12 @@ function hook_image_style_flush($style) {
  * be available on a different schema. This hook is called when the image module
  * builds the uri of an image derivative.
  *
- * Note: If you use a special image derivative uri alteration that stores the
- * image derivatives outside Drupal (for example on a public image service like
- * Flickr), you might need to implement your own flush policy. Implementing
- * hook_image_style_flush() is a good point where you can hook your flush custom
- * actions.
+ * Note: If you use a special uri alteration that stores the image derivatives
+ * outside of public://styles/{image_style}, private://styles/{image_style} or
+ * even outside Drupal (for example, on a public image service like Flickr,
+ * Instagram, etc.), you need to implement your own flush policy. Implementing
+ * hook_image_style_flush() is a good point where you can define your custom
+ * flush actions.
  *
  * @param string $uri
  *   The image style uri to be altered.