diff --git a/core/lib/Drupal/Component/Utility/Random.php b/core/lib/Drupal/Component/Utility/Random.php
index 1aeeb95..aeaa921 100644
--- a/core/lib/Drupal/Component/Utility/Random.php
+++ b/core/lib/Drupal/Component/Utility/Random.php
@@ -262,8 +262,12 @@ public function paragraphs($paragraph_count = 12) {
    *
    * @param string $destination
    *   The absolute file path where the image should be stored.
-   * @param int $min_resolution
-   * @param int $max_resolution
+   * @param string $min_resolution
+   *   A string in the form WIDTHxHEIGHT; for example, '640x480',
+   *   if you want a minimum resolution of 640px width and 480px height.
+   * @param string $max_resolution
+   *   A string in the form WIDTHxHEIGHT; for example, '640x480',
+   *   if you want a maximum resolution of 640px width and 480px height.
    *
    * @return string
    *   Path to image file.