diff --git a/src/Document/Components/ArticleThumbnail.php b/src/Document/Components/ArticleThumbnail.php
new file mode 100644
index 0000000..7bf6c7f
--- /dev/null
+++ b/src/Document/Components/ArticleThumbnail.php
@@ -0,0 +1,137 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TomGould\AppleNews\Document\Components;
+
+/**
+ * Article thumbnail component for custom feed images.
+ *
+ * The article_thumbnail component allows you to specify a custom image
+ * that appears in article feeds and tiles, separate from the main article content.
+ *
+ * @see https://developer.apple.com/documentation/applenewsformat/articlethumbnail
+ */
+final class ArticleThumbnail extends Component
+{
+    /**
+     * The caption for the thumbnail.
+     */
+    private ?string $caption = null;
+
+    /**
+     * The accessibility caption for VoiceOver users.
+     */
+    private ?string $accessibilityCaption = null;
+
+    /**
+     * Whether the image contains explicit content.
+     */
+    private ?bool $explicitContent = null;
+
+    /**
+     * Create a new ArticleThumbnail component.
+     *
+     * @param string $url The URL to the thumbnail image file.
+     */
+    public function __construct(
+        private readonly string $url
+    ) {
+    }
+
+    /**
+     * Create an ArticleThumbnail from a URL.
+     *
+     * @param string $url The image URL.
+     *
+     * @return self A new ArticleThumbnail instance.
+     */
+    public static function fromUrl(string $url): self
+    {
+        return new self($url);
+    }
+
+    /**
+     * Create an ArticleThumbnail from a bundle file reference.
+     *
+     * @param string $filename The filename in the article bundle.
+     *
+     * @return self A new ArticleThumbnail instance.
+     */
+    public static function fromBundle(string $filename): self
+    {
+        return new self('bundle://' . $filename);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getRole(): string
+    {
+        return 'article_thumbnail';
+    }
+
+    /**
+     * Set the thumbnail caption.
+     *
+     * @param string $caption The caption text.
+     *
+     * @return $this
+     */
+    public function setCaption(string $caption): self
+    {
+        $this->caption = $caption;
+        return $this;
+    }
+
+    /**
+     * Set the accessibility caption for VoiceOver.
+     *
+     * @param string $caption The accessibility caption.
+     *
+     * @return $this
+     */
+    public function setAccessibilityCaption(string $caption): self
+    {
+        $this->accessibilityCaption = $caption;
+        return $this;
+    }
+
+    /**
+     * Set whether the image contains explicit content.
+     *
+     * @param bool $explicit Whether the content is explicit.
+     *
+     * @return $this
+     */
+    public function setExplicitContent(bool $explicit): self
+    {
+        $this->explicitContent = $explicit;
+        return $this;
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @return array<string, mixed>
+     */
+    public function jsonSerialize(): array
+    {
+        $data = $this->getBaseProperties();
+        $data['URL'] = $this->url;
+
+        if ($this->caption !== null) {
+            $data['caption'] = $this->caption;
+        }
+
+        if ($this->accessibilityCaption !== null) {
+            $data['accessibilityCaption'] = $this->accessibilityCaption;
+        }
+
+        if ($this->explicitContent !== null) {
+            $data['explicitContent'] = $this->explicitContent;
+        }
+
+        return $data;
+    }
+}
diff --git a/src/Document/Components/ArticleTitle.php b/src/Document/Components/ArticleTitle.php
new file mode 100644
index 0000000..cd859d3
--- /dev/null
+++ b/src/Document/Components/ArticleTitle.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TomGould\AppleNews\Document\Components;
+
+/**
+ * Article title component with enhanced formatting options.
+ *
+ * The article_title component is similar to the title component but offers
+ * additional formatting options and is specifically designed for the main
+ * article title that appears in feeds.
+ *
+ * @see https://developer.apple.com/documentation/applenewsformat/articletitle
+ */
+final class ArticleTitle extends TextComponent
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function getRole(): string
+    {
+        return 'article_title';
+    }
+}
diff --git a/src/Document/Components/Logo.php b/src/Document/Components/Logo.php
index 97042c6..8c79033 100644
--- a/src/Document/Components/Logo.php
+++ b/src/Document/Components/Logo.php
@@ -23,6 +23,11 @@ final class Logo extends Component
      */
     private ?string $accessibilityCaption = null;
 
+    /**
+     * Whether the image contains explicit content.
+     */
+    private ?bool $explicitContent = null;
+
     /**
      * Create a new Logo component.
      *
@@ -91,6 +96,19 @@ public function setAccessibilityCaption(string $caption): self
         return $this;
     }
 
+    /**
+     * Set whether the image contains explicit content.
+     *
+     * @param bool $explicit Whether the content is explicit.
+     *
+     * @return $this
+     */
+    public function setExplicitContent(bool $explicit): self
+    {
+        $this->explicitContent = $explicit;
+        return $this;
+    }
+
     /**
      * {@inheritdoc}
      *
@@ -112,6 +130,10 @@ public function jsonSerialize(): array
             $data['accessibilityCaption'] = $this->accessibilityCaption;
         }
 
+        if ($this->explicitContent !== null) {
+            $data['explicitContent'] = $this->explicitContent;
+        }
+
         return $data;
     }
 }
diff --git a/src/Document/Components/TextComponent.php b/src/Document/Components/TextComponent.php
index 6437119..a535fb1 100644
--- a/src/Document/Components/TextComponent.php
+++ b/src/Document/Components/TextComponent.php
@@ -20,6 +20,9 @@ abstract class TextComponent extends Component
     /** @var string|null The text format (none, html, markdown). */
     protected ?string $format = null;
 
+    /** @var array<array<string, mixed>>|null Additions (links) applied to text ranges. */
+    protected ?array $additions = null;
+
     /**
      * @param string $text The raw text content.
      */
@@ -61,6 +64,22 @@ public function setFormat(string $format): static
         return $this;
     }
 
+    /**
+     * Set additions (link ranges) for the text component.
+     *
+     * Additions allow you to apply links to specific ranges of text.
+     * Note: Additions are not supported when format is 'html' or 'markdown'.
+     *
+     * @param array<array<string, mixed>> $additions Array of addition objects with rangeStart, rangeLength, and link.
+     * @return static
+     * @see https://developer.apple.com/documentation/applenewsformat/addition
+     */
+    public function setAdditions(array $additions): static
+    {
+        $this->additions = $additions;
+        return $this;
+    }
+
     /**
      * @return array<string, mixed>
      */
@@ -81,6 +100,10 @@ public function jsonSerialize(): array
             $data['format'] = $this->format;
         }
 
+        if ($this->additions !== null) {
+            $data['additions'] = $this->additions;
+        }
+
         return $data;
     }
 }
diff --git a/src/Request/MultipartBuilder.php b/src/Request/MultipartBuilder.php
index 660fbbb..392ad4b 100644
--- a/src/Request/MultipartBuilder.php
+++ b/src/Request/MultipartBuilder.php
@@ -210,6 +210,7 @@ private function guessImageContentType(string $filename): string
             'jpg', 'jpeg' => 'image/jpeg',
             'png' => 'image/png',
             'gif' => 'image/gif',
+            'webp' => 'image/webp',
             default => 'application/octet-stream',
         };
     }
diff --git a/tests/Document/Components/TextComponentAdditionsTest.php b/tests/Document/Components/TextComponentAdditionsTest.php
new file mode 100644
index 0000000..f499885
--- /dev/null
+++ b/tests/Document/Components/TextComponentAdditionsTest.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+namespace TomGould\AppleNews\Tests\Document\Components;
+
+use TomGould\AppleNews\Document\Components\Body;
+use PHPUnit\Framework\TestCase;
+
+final class TextComponentAdditionsTest extends TestCase
+{
+    public function testAdditionsCanBeSet(): void
+    {
+        $body = new Body('Hello world, check this link!');
+        
+        $additions = [
+            [
+                'type' => 'link',
+                'rangeStart' => 19,
+                'rangeLength' => 4,
+                'URL' => 'https://example.com',
+            ],
+        ];
+        
+        $body->setAdditions($additions);
+        
+        $data = $body->jsonSerialize();
+        
+        $this->assertArrayHasKey('additions', $data);
+        $this->assertEquals($additions, $data['additions']);
+    }
+
+    public function testAdditionsNotIncludedWhenNull(): void
+    {
+        $body = new Body('Simple text without links');
+        
+        $data = $body->jsonSerialize();
+        
+        $this->assertArrayNotHasKey('additions', $data);
+    }
+}