diff --git a/core/lib/Drupal/Core/ImageToolkit/ImageToolkitInterface.php b/core/lib/Drupal/Core/ImageToolkit/ImageToolkitInterface.php
index 214923f..0ac928b 100644
--- a/core/lib/Drupal/Core/ImageToolkit/ImageToolkitInterface.php
+++ b/core/lib/Drupal/Core/ImageToolkit/ImageToolkitInterface.php
@@ -174,26 +174,22 @@ public function save(ImageInterface $image, $destination);
   public function getInfo(ImageInterface $image);
 
   /**
-   * Gets toolkit requirements in a format suitable for hook_requirements().
+   * Verifies if the image toolkit is set up correctly.
    *
-   * @return array
-   *   An associative requirements array as is returned by hook_requirements().
-   *   If the toolkit claims no requirements to the system, returns an empty
-   *   array. The array can have arbitrary keys and they do not have to be
-   *   prefixed by e.g. the module name or toolkit ID, as the system will make
-   *   the keys globally unique.
-   *
-   * @see hook_requirements()
-   */
-  public function requirements();
-
-  /**
-   * Verifies Image Toolkit is set up correctly.
+   * @param array $requirements
+   *   An associative requirements array passed by reference in the same format
+   *   as is returned by hook_requirements(). If the toolkit claims no
+   *   requirements to the system, no items will be added to this array. The
+   *   method can add new items with arbitrary keys. Those keys do not have to
+   *   be prefixed by e.g. the module name or toolkit ID, as the system will
+   *   make the keys globally unique.
    *
    * @return bool
-   *   True if the GD toolkit is available on this machine.
+   *   TRUE if the toolkit is available on this machine.
+   *
+   * @see hook_requirements()
    */
-  public static function isAvailable();
+  public static function availability(array &$requirements = array());
 
   /**
    * Returns a list of image types supported by the toolkit.
diff --git a/core/lib/Drupal/Core/ImageToolkit/ImageToolkitManager.php b/core/lib/Drupal/Core/ImageToolkit/ImageToolkitManager.php
index 43686ff..3c53344 100644
--- a/core/lib/Drupal/Core/ImageToolkit/ImageToolkitManager.php
+++ b/core/lib/Drupal/Core/ImageToolkit/ImageToolkitManager.php
@@ -84,7 +84,7 @@ public function getAvailableToolkits() {
     $output = array();
     foreach ($toolkits as $id => $definition) {
       // Only allow modules that aren't marked as unavailable.
-      if (call_user_func($definition['class'] . '::isAvailable')) {
+      if (call_user_func($definition['class'] . '::availability')) {
         $output[$id] = $definition;
       }
     }
diff --git a/core/modules/image/image.install b/core/modules/image/image.install
index 2ef40a2..4dba3b9 100644
--- a/core/modules/image/image.install
+++ b/core/modules/image/image.install
@@ -33,11 +33,13 @@ function image_requirements($phase) {
     return array();
   }
 
-  $toolkit = \Drupal::service('image.toolkit.manager')->getDefaultToolkit();
   $requirements = array();
-  foreach ($toolkit->requirements() as $key => $requirement) {
+  $toolkit = \Drupal::service('image.toolkit.manager')->getDefaultToolkit();
+  $toolkit->availability($requirements);
+  foreach ($requirements as $key => $requirement) {
     $namespaced_key = 'image.toolkit.' . $toolkit->getPluginId() . '.' . $key;
     $requirements[$namespaced_key] = $requirement;
+    unset($requirements[$key]);
   }
 
   return $requirements;
diff --git a/core/modules/system/lib/Drupal/system/Plugin/ImageToolkit/GDToolkit.php b/core/modules/system/lib/Drupal/system/Plugin/ImageToolkit/GDToolkit.php
index 810c16d..22bda91 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/ImageToolkit/GDToolkit.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/ImageToolkit/GDToolkit.php
@@ -275,10 +275,15 @@ public function createTmp(ImageInterface $image, $width, $height) {
   /**
    * {@inheritdoc}
    */
-  public function requirements() {
-    $requirements = array();
+  public static function availability(array &$requirements = array()) {
+    if ($check = get_extension_funcs('gd')) {
+      $available = in_array('imagegd2', $check);
+    }
+    else {
+      $available = FALSE;
+    }
 
-    if (static::isAvailable()) {
+    if ($available) {
       $info = gd_info();
       $requirements['rotate_desaturate'] = array(
         'value' => $info['GD Version'],
@@ -299,20 +304,7 @@ public function requirements() {
     }
     $requirements['rotate_desaturate']['title'] = t('GD library rotate and desaturate effects');
 
-    return $requirements;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function isAvailable() {
-    if ($check = get_extension_funcs('gd')) {
-      if (in_array('imagegd2', $check)) {
-        // GD2 support is available.
-        return TRUE;
-      }
-    }
-    return FALSE;
+    return $available;
   }
 
   /**
diff --git a/core/modules/system/tests/modules/image_test/lib/Drupal/image_test/Plugin/ImageToolkit/BrokenToolkit.php b/core/modules/system/tests/modules/image_test/lib/Drupal/image_test/Plugin/ImageToolkit/BrokenToolkit.php
index e5ead27..ae6d64d 100644
--- a/core/modules/system/tests/modules/image_test/lib/Drupal/image_test/Plugin/ImageToolkit/BrokenToolkit.php
+++ b/core/modules/system/tests/modules/image_test/lib/Drupal/image_test/Plugin/ImageToolkit/BrokenToolkit.php
@@ -20,7 +20,7 @@ class BrokenToolkit extends TestToolkit {
   /**
    * {@inheritdoc}
    */
-  public static function isAvailable() {
+  public static function availability(array &$requirements = array()) {
     return FALSE;
   }
 }
diff --git a/core/modules/system/tests/modules/image_test/lib/Drupal/image_test/Plugin/ImageToolkit/TestToolkit.php b/core/modules/system/tests/modules/image_test/lib/Drupal/image_test/Plugin/ImageToolkit/TestToolkit.php
index d2fcdef..88c1731 100644
--- a/core/modules/system/tests/modules/image_test/lib/Drupal/image_test/Plugin/ImageToolkit/TestToolkit.php
+++ b/core/modules/system/tests/modules/image_test/lib/Drupal/image_test/Plugin/ImageToolkit/TestToolkit.php
@@ -126,14 +126,7 @@ protected function logCall($op, $args) {
   /**
    * {@inheritdoc}
    */
-  public function requirements() {
-    return array();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function isAvailable() {
+  public static function availability(array &$requirements = array()) {
     return TRUE;
   }