diff --git a/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php b/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php
index b88a220..21b35bd 100644
--- a/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php
+++ b/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php
@@ -26,7 +26,7 @@ class GDToolkit extends ImageToolkitBase {
    *
    * @var resource
    */
-  protected $resource;
+  protected $resource = NULL;
 
   /**
    * Image type represented by a PHP IMAGETYPE_* constant (e.g. IMAGETYPE_JPEG).
@@ -40,7 +40,7 @@ class GDToolkit extends ImageToolkitBase {
    *
    * @var array
    */
-  protected $preLoadInfo;
+  protected $preLoadInfo = NULL;
 
   /**
    * Sets the GD image resource.
@@ -51,8 +51,8 @@ class GDToolkit extends ImageToolkitBase {
    * @return $this
    */
   public function setResource($resource) {
-    if (isset($this->preLoadInfo)) {
-      unset($this->preLoadInfo);
+    if ($this->preLoadInfo) {
+      $this->preLoadInfo = NULL;
     }
     $this->resource = $resource;
     return $this;
@@ -65,7 +65,7 @@ public function setResource($resource) {
    *   The GD image resource, or NULL if not available.
    */
   public function getResource() {
-    if (!isset($this->resource)) {
+    if (!$this->resource) {
       $this->load();
     }
     return $this->resource;
@@ -110,8 +110,8 @@ protected function load() {
 
     $function = 'imagecreatefrom' . image_type_to_extension($this->getType(), FALSE);
     if (function_exists($function) && $resource = $function($this->getImage()->getSource())) {
+      $this->setResource($resource);
       if (imageistruecolor($resource)) {
-        $this->setResource($resource);
         return TRUE;
       }
       else {
@@ -133,7 +133,7 @@ protected function load() {
    * {@inheritdoc}
    */
   public function isValid() {
-    return isset($this->preLoadInfo) || isset($this->resource);
+    return ((bool) $this->preLoadInfo || (bool) $this->resource);
   }
 
   /**
@@ -246,7 +246,7 @@ public function createTmp($type, $width, $height) {
    * {@inheritdoc}
    */
   public function getWidth() {
-    if (isset($this->preLoadInfo)) {
+    if ($this->preLoadInfo) {
       return $this->preLoadInfo[0];
     }
     elseif ($res = $this->getResource()) {
@@ -261,7 +261,7 @@ public function getWidth() {
    * {@inheritdoc}
    */
   public function getHeight() {
-    if (isset($this->preLoadInfo)) {
+    if ($this->preLoadInfo) {
       return $this->preLoadInfo[1];
     }
     elseif ($res = $this->getResource()) {