diff --git a/src/Plugin/Field/FieldFormatter/ImagePopupFieldFormatter.php b/src/Plugin/Field/FieldFormatter/ImagePopupFieldFormatter.php
index 8874c9f..baa30eb 100644
--- a/src/Plugin/Field/FieldFormatter/ImagePopupFieldFormatter.php
+++ b/src/Plugin/Field/FieldFormatter/ImagePopupFieldFormatter.php
@@ -1,16 +1,8 @@
 <?php
 
-/**
- * @file
- * Contains \Drupal\image_popup\Plugin\Field\FieldFormatter\ImagePopupFieldFormatter.
- */
-
 namespace Drupal\image_popup\Plugin\Field\FieldFormatter;
 
-use Drupal\Component\Utility\Html;
-use Drupal\Core\Field\FieldItemInterface;
 use Drupal\Core\Field\FieldItemListInterface;
-use Drupal\Core\Field\FormatterBase;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\image\Entity\ImageStyle;
 use Drupal\image\Plugin\Field\FieldFormatter\ImageFormatterBase;
@@ -25,6 +17,8 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
 /**
  * Plugin implementation of the 'image_popup_field_formatter' formatter.
  *
+ * Contains \Drupal\image_popup\Plugin\Field\FieldFormatter\ImagePopupFieldFormatter.
+ *
  * @FieldFormatter(
  *   id = "image_popup_field_formatter",
  *   label = @Translation("Image Popup"),
@@ -101,7 +95,7 @@ class ImagePopupFieldFormatter extends ImageFormatterBase implements ContainerFa
       $container->get('current_user'),
       $container->get('link_generator'),
       $container->get('entity.manager')->getStorage('image_style')
-      //$container->get('entity.manager')->getStorage('image_style_popup')
+      // $container->get('entity.manager')->getStorage('image_style_popup')
     );
   }
 
@@ -109,11 +103,11 @@ class ImagePopupFieldFormatter extends ImageFormatterBase implements ContainerFa
    * {@inheritdoc}
    */
   public static function defaultSettings() {
-    return array(
+    return [
       'image_style' => '',
       'image_style_popup' => '',
       'image_link' => '',
-    ) + parent::defaultSettings();
+    ] + parent::defaultSettings();
   }
 
   /**
@@ -122,29 +116,29 @@ class ImagePopupFieldFormatter extends ImageFormatterBase implements ContainerFa
   public function settingsForm(array $form, FormStateInterface $form_state) {
     $image_styles = image_style_options(FALSE);
     $elements = parent::settingsForm($form, $form_state);
-    $elements['image_style'] = array(
+    $elements['image_style'] = [
       '#title' => t('Image style'),
       '#type' => 'select',
       '#default_value' => $this->getSetting('image_style'),
       '#empty_option' => t('None (original image)'),
       '#options' => $image_styles,
-      '#description' => array(
+      '#description' => [
         '#markup' => $this->linkGenerator->generate($this->t('Configure Image Styles'), new Url('entity.image_style.collection')),
         '#access' => $this->currentUser->hasPermission('administer image styles'),
-      ),
-    );
+      ],
+    ];
 
-    $elements['image_style_popup'] = array(
+    $elements['image_style_popup'] = [
       '#title' => t('Popup Image style'),
       '#type' => 'select',
       '#default_value' => $this->getSetting('image_style_popup'),
       '#empty_option' => t('None (original image)'),
       '#options' => $image_styles,
-      '#description' => array(
+      '#description' => [
         '#markup' => $this->linkGenerator->generate($this->t('Configure Image Styles'), new Url('entity.image_style.collection')),
         '#access' => $this->currentUser->hasPermission('administer image styles'),
-      ),
-    );
+      ],
+    ];
 
     return $elements;
   }
@@ -153,7 +147,7 @@ class ImagePopupFieldFormatter extends ImageFormatterBase implements ContainerFa
    * {@inheritdoc}
    */
   public function settingsSummary() {
-    $summary = array();
+    $summary = [];
 
     $image_styles = image_style_options(FALSE);
     // Unset possible 'No defined styles' option.
@@ -162,7 +156,7 @@ class ImagePopupFieldFormatter extends ImageFormatterBase implements ContainerFa
     // their styles in code.
     $image_style_setting = $this->getSetting('image_style');
     if (isset($image_styles[$image_style_setting])) {
-      $summary[] = t('Image style: @style', array('@style' => $image_styles[$image_style_setting]));
+      $summary[] = t('Image style: @style', ['@style' => $image_styles[$image_style_setting]]);
     }
     else {
       $summary[] = t('Original image');
@@ -174,22 +168,26 @@ class ImagePopupFieldFormatter extends ImageFormatterBase implements ContainerFa
    * {@inheritdoc}
    */
   public function viewElements(FieldItemListInterface $items, $langcode) {
-    $elements = array();
+    $elements = [];
     $files = $this->getEntitiesToView($items, $langcode);
-
+    // If there are no files, return an empty element.
+    if (!isset($files[0])) {
+      return [];
+    }
     $image_style_popup = $this->getSetting('image_style_popup');
     $image_style_name = $this->getSetting('image_style');
     $image_fid = $files[0]->get('fid')->getValue()[0]['value'];
 
-
     $image_style = ImageStyle::load($image_style_name);
     $config_name = "image.style." . $image_style_popup;
     $image_style_popup_settings = \Drupal::config($config_name)->getRawData();
-    //$image_style_popup_settings = entity_load('image_style', $image_style_popup);
+    // $image_style_popup_settings = entity_load('image_style', $image_style_popup);
     $popup_width = 750;
-    foreach ($image_style_popup_settings['effects'] as $key => $effect) {
-      if ($effect['id'] == 'image_scale') {
-        $popup_width = $effect['data']['width'];
+    if (isset($image_style_popup_settings['effects'])) {
+      foreach ($image_style_popup_settings['effects'] as $key => $effect) {
+        if ($effect['id'] == 'image_scale') {
+          $popup_width = $effect['data']['width'];
+        }
       }
     }
 
@@ -205,10 +203,10 @@ class ImagePopupFieldFormatter extends ImageFormatterBase implements ContainerFa
       }
       global $base_url;
       $img = "<img src='" . $absolute_path . "'><img>";
-      $img_link = "<a href='" . $base_url . "/image_popup/render/" . $image_fid. "/" .  $image_style_popup. "' class='use-ajax' data-dialog-type='modal' data-dialog-options='{\"width\":". $popup_width ."}'>" . $img . "</a>";
-      $elements[$delta] = array(
+      $img_link = "<a href='" . $base_url . "/image_popup/render/" . $image_fid . "/" . $image_style_popup . "' class='use-ajax' data-dialog-type='modal' data-dialog-options='{\"width\":" . $popup_width . "}'>" . $img . "</a>";
+      $elements[$delta] = [
         '#markup' => $img_link,
-      );
+      ];
 
     }