diff -u b/src/Plugin/diff/Field/ImageFieldBuilder.php b/src/Plugin/diff/Field/ImageFieldBuilder.php
--- b/src/Plugin/diff/Field/ImageFieldBuilder.php
+++ b/src/Plugin/diff/Field/ImageFieldBuilder.php
@@ -58,13 +58,13 @@
         if ($this->configuration['image_metadata']) {
           if (isset($values['target_id'])) {
             $image = $fileManager->load($values['target_id']);
-            $result[$field_key][] = $this->t('File size: @size', ['@size' => format_size($image->getSize())]);
-            $result[$field_key][] = $this->t('MIME Type: @mime', ['@mime' => $image->getMimeType()]);
+            $result[$field_key]['size'] = $this->t('File size: @size', ['@size' => format_size($image->getSize())]);
+            $result[$field_key]['type'] = $this->t('MIME Type: @mime', ['@mime' => $image->getMimeType()]);
             if (!empty($values['width'])) {
-              $result[$field_key][] = $this->t('Width: @width', ['@width' => $values['width']]);
+              $result[$field_key]['width'] = $this->t('Width: @width', ['@width' => $values['width']]);
             }
             if (!empty($values['height'])) {
-              $result[$field_key][] = $this->t('Height: @height', ['@height' => $values['height']]);
+              $result[$field_key]['height'] = $this->t('Height: @height', ['@height' => $values['height']]);
             }
           }
         }
diff -u b/src/Tests/DiffPluginFileTest.php b/src/Tests/DiffPluginFileTest.php
--- b/src/Tests/DiffPluginFileTest.php
+++ b/src/Tests/DiffPluginFileTest.php
@@ -205,6 +205,8 @@
     $this->assertText('Image: image-test-transparent-indexed.gif');
     // Image title must be absent since it is not set in previous revisions.
     $this->assertText('Title');
+    $this->assertText('Width: 20');
+    $this->assertText('Height: 17');
 
     // Enable Title field in instance settings.
     $this->drupalPostForm('admin/structure/types/manage/article/fields/node.article.field_image', [
@@ -225,6 +227,8 @@
     $this->assertEqual(htmlspecialchars_decode(strip_tags($rows[2]->td[5]->asXML())), 'Alt: Image alt updated new');
     $this->assertEqual(htmlspecialchars_decode(strip_tags($rows[3]->td[2]->asXML())), 'Title: ');
     $this->assertEqual(htmlspecialchars_decode(strip_tags($rows[3]->td[5]->asXML())), 'Title: Image title updated');
+    $this->assertEqual(htmlspecialchars_decode(strip_tags($rows[4]->td[2]->asXML())), 'File size: 140 bytes');
+    $this->assertEqual(htmlspecialchars_decode(strip_tags($rows[4]->td[5]->asXML())), 'File size: 140 bytes');
 
     // Show File ID.
     $this->drupalGet('admin/config/content/diff/fields');