diff --git a/modules/image/image.module b/modules/image/image.module
index 71fba37971..91419048f2 100644
--- a/modules/image/image.module
+++ b/modules/image/image.module
@@ -583,8 +583,10 @@ function image_styles() {
           $style['storage'] = IMAGE_STORAGE_DEFAULT;
           foreach ($style['effects'] as $key => $effect) {
             $definition = image_effect_definition_load($effect['name']);
-            $effect = array_merge($definition, $effect);
-            $style['effects'][$key] = $effect;
+            if ($definition) {
+              $effect = array_merge($definition, $effect);
+              $style['effects'][$key] = $effect;
+            }
           }
           $styles[$style_name] = $style;
         }
diff --git a/modules/image/image.test b/modules/image/image.test
index 07eb4cedc1..e5bb220d37 100644
--- a/modules/image/image.test
+++ b/modules/image/image.test
@@ -31,7 +31,7 @@ class ImageFieldTestCase extends DrupalWebTestCase {
   protected $admin_user;
 
   function setUp() {
-    parent::setUp('image');
+    parent::setUp(array_unique(array_merge(array('image'), array_pop(func_get_args()))));
     $this->admin_user = $this->drupalCreateUser(array('access content', 'access administration pages', 'administer site configuration', 'administer content types', 'administer nodes', 'create article content', 'edit any article content', 'delete any article content', 'administer image styles', 'administer fields'));
     $this->drupalLogin($this->admin_user);
   }
@@ -573,6 +573,10 @@ class ImageAdminStylesUnitTest extends ImageFieldTestCase {
     );
   }
 
+  function setUp() {
+    parent::setUp('image_module_test', 'image_module_styles_test');
+  }
+
   /**
    * Given an image style, generate an image.
    */
@@ -893,6 +897,20 @@ class ImageAdminStylesUnitTest extends ImageFieldTestCase {
     $this->drupalGet('node/' . $nid);
     $this->assertRaw(check_plain(image_style_url('thumbnail', $node->{$field_name}[LANGUAGE_NONE][0]['uri'])), format_string('Image displayed using style replacement style.'));
   }
+
+  /**
+   * Test adding an effect to a style then removing the providing module.
+   */
+  function testOrphanedEffect() {
+    $style_name = 'test_image_style';
+    $style_label = 'Test Image Style';
+
+    module_disable(array('image_module_test'), FALSE);
+    $this->drupalGet('admin/config/media/image-styles');
+    $this->assertText($style_label, 'Image style with an orphaned effect displayed in the list of styles.');
+    //$this->drupalGet('admin/config/media/image-styles/edit/' . $style_name);
+    //$this->assertRaw(t('Edit %name style', array('%name' => $style_label)), 'Image style with an orphaned effect remains editable.');
+  }
 }
 
 /**
diff --git a/modules/image/tests/image_module_styles_test.info b/modules/image/tests/image_module_styles_test.info
new file mode 100644
index 0000000000..aa6a975c8a
--- /dev/null
+++ b/modules/image/tests/image_module_styles_test.info
@@ -0,0 +1,7 @@
+name = Image Styles test
+description = Provides additional hook implementations for testing Image Styles functionality.
+package = Core
+version = VERSION
+core = 7.x
+files[] = image_module_styles_test.module
+hidden = TRUE
diff --git a/modules/image/tests/image_module_styles_test.module b/modules/image/tests/image_module_styles_test.module
new file mode 100644
index 0000000000..79929d9399
--- /dev/null
+++ b/modules/image/tests/image_module_styles_test.module
@@ -0,0 +1,29 @@
+<?php
+
+/**
+ * @file
+ * Provides additional Image module hook implementations for testing purposes.
+ */
+
+/**
+ * Implements hook_image_default_styles().
+ */
+function image_module_styles_test_image_default_styles() {
+  $styles = array();
+
+  $styles['test_image_style'] = array(
+    'label' => 'Test Image Style',
+    'effects' => array(
+      array(
+        'name' => 'image_scale',
+        'data' => array('width' => 100, 'height' => 100, 'upscale' => 1),
+        'weight' => 0,
+      ),
+      array(
+        'name' => 'image_module_test_null',
+      ),
+    )
+  );
+
+  return $styles;
+}
diff --git a/modules/image/tests/image_module_test.module b/modules/image/tests/image_module_test.module
index fc66d9b8b7..e7ae716e7a 100644
--- a/modules/image/tests/image_module_test.module
+++ b/modules/image/tests/image_module_test.module
@@ -20,7 +20,8 @@ function image_module_test_file_download($uri) {
 function image_module_test_image_effect_info() {
   $effects = array(
     'image_module_test_null' => array(
-    'effect callback' => 'image_module_test_null_effect',
+      'label' => 'image_module_test_null',
+      'effect callback' => 'image_module_test_null_effect',
     ),
   );
 
@@ -38,7 +39,7 @@ function image_module_test_image_effect_info() {
  * @return
  *   TRUE
  */
-function image_module_test_null_effect(array &$image, array $data) {
+function image_module_test_null_effect(&$image, array $data) {
   return TRUE;
 }