diff --git a/core/includes/image.inc b/core/includes/image.inc
index ccc36a4..cfa57b1 100644
--- a/core/includes/image.inc
+++ b/core/includes/image.inc
@@ -65,7 +65,7 @@ function image_get_toolkit() {
 
   if (!isset($toolkit)) {
     $toolkits = image_get_available_toolkits();
-    $toolkit = variable_get('image_toolkit', 'gd');
+    $toolkit = config('system.image')->get('toolkit');
     if (!isset($toolkits[$toolkit]) || !function_exists('image_' . $toolkit . '_load')) {
       // The selected toolkit isn't available so return the first one found. If
       // none are available this will return FALSE.
diff --git a/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
index 4a4ba0e..380b770 100644
--- a/core/modules/system/system.admin.inc
+++ b/core/modules/system/system.admin.inc
@@ -1837,7 +1837,6 @@ function system_image_toolkit_settings() {
   $current_toolkit = image_get_toolkit();
 
   if (count($toolkits_available) == 0) {
-    variable_del('image_toolkit');
     $form['image_toolkit_help'] = array(
       '#markup' => t("No image toolkits were detected. Drupal includes support for <a href='!gd-link'>PHP's built-in image processing functions</a> but they were not detected on this system. You should consult your system administrator to have them enabled, or try using a third party toolkit.", array('gd-link' => url('http://php.net/gd'))),
     );
@@ -1848,12 +1847,12 @@ function system_image_toolkit_settings() {
     $form['image_toolkit'] = array(
       '#type' => 'radios',
       '#title' => t('Select an image processing toolkit'),
-      '#default_value' => variable_get('image_toolkit', $current_toolkit),
+      '#default_value' => config('system.image')->get('toolkit'),
       '#options' => $toolkits_available
     );
   }
   else {
-    variable_set('image_toolkit', key($toolkits_available));
+    config('system.image')->set('toolkit', key($toolkits_available))->save();
   }
 
   // Get the toolkit's settings form.
diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index 9d98678..6514f59 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -2180,6 +2180,17 @@ function system_update_8050() {
 }
 
 /**
+ * Moves system image settings from variable to config.
+ *
+ * @ingroup config_upgrade
+ */
+function system_update_8051() {
+  update_variables_to_config('system.image', array(
+    'image_toolkit' => 'current_toolkit',
+  ));
+}
+
+/**
  * @} End of "defgroup updates-7.x-to-8.x".
  * The next series of updates should start at 9000.
  */