diff --git a/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php b/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php
index 08ff4f6..5e8a0ab 100644
--- a/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php
+++ b/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php
@@ -381,7 +381,7 @@ public function extensionToImageType($extension) {
    *   An array of available image types. An image type is represented by a PHP
    *   IMAGETYPE_* constant (e.g. IMAGETYPE_JPEG, IMAGETYPE_PNG, etc.).
    */
-  public static function supportedTypes() {
+  protected static function supportedTypes() {
     return array(IMAGETYPE_PNG, IMAGETYPE_JPEG, IMAGETYPE_GIF);
   }
 }
diff --git a/core/modules/system/src/Plugin/ImageToolkit/Operation/gd/Convert.php b/core/modules/system/src/Plugin/ImageToolkit/Operation/gd/Convert.php
index 49f7fbe..51d79aa 100644
--- a/core/modules/system/src/Plugin/ImageToolkit/Operation/gd/Convert.php
+++ b/core/modules/system/src/Plugin/ImageToolkit/Operation/gd/Convert.php
@@ -47,19 +47,29 @@ protected function validateArguments(array $arguments) {
    * {@inheritdoc}
    */
   protected function execute(array $arguments) {
-    $type = $this->getToolkit()->extensionToImageType($arguments['extension']);
-
-    $res = $this->getToolkit()->createTmp($type, $this->getToolkit()->getWidth(), $this->getToolkit()->getHeight());
-    if (!imagecopyresampled($res, $this->getToolkit()->getResource(), 0, 0, 0, 0, $this->getToolkit()->getWidth(), $this->getToolkit()->getHeight(), $this->getToolkit()->getWidth(), $this->getToolkit()->getHeight())) {
-      return FALSE;
+    // Create a new resource of the required dimensions and format, and copy
+    // the original resource on it with resampling. Destroy the original
+    // resource upon success.
+    $width = $this->getToolkit()->getWidth();
+    $height = $this->getToolkit()->getHeight();
+    $original_resource = $this->getToolkit()->getResource();
+    $original_type = $this->getToolkit()->getType();
+    $data = array(
+      'width' => $width,
+      'height' => $height,
+      'extension' => $arguments['extension'],
+      'transparent_color' => $this->getToolkit()->getTransparentColor()
+    );
+    if ($this->getToolkit()->apply('create_new', $data)) {
+      if (imagecopyresampled($this->getToolkit()->getResource(), $original_resource, 0, 0, 0, 0, $width, $height, $width, $height)) {
+        imagedestroy($original_resource);
+        return TRUE;
+      }
+      // In case of error, reset resource and type to as it was.
+      $this->getToolkit()->setResource($original_resource);
+      $this->getToolkit()->setType($original_type);
     }
-    imagedestroy($this->getToolkit()->getResource());
-
-    // Update the image object.
-    $this->getToolkit()->setType($type);
-    $this->getToolkit()->setResource($res);
-
-    return TRUE;
+    return FALSE;
   }
 
 }
diff --git a/core/modules/system/src/Plugin/ImageToolkit/Operation/gd/CreateNew.php b/core/modules/system/src/Plugin/ImageToolkit/Operation/gd/CreateNew.php
index 3a762e1..126f53c 100644
--- a/core/modules/system/src/Plugin/ImageToolkit/Operation/gd/CreateNew.php
+++ b/core/modules/system/src/Plugin/ImageToolkit/Operation/gd/CreateNew.php
@@ -81,12 +81,7 @@ protected function validateArguments(array $arguments) {
    */
   protected function execute(array $arguments) {
     // Get the image type.
-    $type = FALSE;
-    foreach ($this->getToolkit()->supportedTypes() as $type) {
-      if (image_type_to_extension($type, FALSE) === $arguments['extension']) {
-        break;
-      }
-    }
+    $type = $this->getToolkit()->extensionToImageType($arguments['extension']);
 
     // Create the resource.
     if (!$res = imagecreatetruecolor($arguments['width'], $arguments['height'])) {