diff --git a/src/Twig/ArticleCardCoverExtension.php b/src/Twig/ArticleCardCoverExtension.php
index d2abd44..16b0545 100644
--- a/src/Twig/ArticleCardCoverExtension.php
+++ b/src/Twig/ArticleCardCoverExtension.php
@@ -43,27 +43,23 @@ final class ArticleCardCoverExtension extends AbstractExtension
         return [
             new TwigFunction('article_card_cover', $this->articleCardCover(...)),
             new TwigFunction('article_og_image', $this->articleOgImage(...)),
+            new TwigFunction('site_og_image', $this->siteOgImage(...)),
         ];
     }
 
     /**
-     * Absolute URL + whether to emit og:image:width/height (1200×630) for the site default OG JPEG only.
+     * Branded site Open Graph image (home, category lists, base layout default): not tied to any article or author.
      *
      * @return array{href: string, use_default_dimensions: bool}
      */
-    public function articleOgImage(?string $articleImage, ?string $pubkeyHex): array
+    public function siteOgImage(): array
     {
-        $cover = $this->articleCardCover($articleImage, $pubkeyHex);
-        $defaultCover = $this->defaultSiteImageUrl();
         $useDefaultDimensions = false;
-        $chosen = $cover;
-        if ($chosen === $defaultCover) {
-            try {
-                $chosen = $this->packages->getUrl(self::OG_FALLBACK_PACKAGE_IMAGE);
-                $useDefaultDimensions = true;
-            } catch (Throwable) {
-                $useDefaultDimensions = false;
-            }
+        try {
+            $chosen = $this->packages->getUrl(self::OG_FALLBACK_PACKAGE_IMAGE);
+            $useDefaultDimensions = true;
+        } catch (Throwable) {
+            $chosen = $this->defaultSiteImageUrl();
         }
 
         return [
@@ -72,6 +68,26 @@ final class ArticleCardCoverExtension extends AbstractExtension
         ];
     }
 
+    /**
+     * Absolute URL + whether to emit og:image:width/height (1200×630) for the site default OG JPEG only.
+     *
+     * Unlike {@see articleCardCover}, this never uses the author’s Nostr profile picture: crawlers and
+     * in-app link previews should get the article hero or the branded {@see OG_FALLBACK_PACKAGE_IMAGE}.
+     *
+     * @return array{href: string, use_default_dimensions: bool}
+     */
+    public function articleOgImage(?string $articleImage, ?string $_pubkeyHex): array
+    {
+        if ($articleImage !== null && trim($articleImage) !== '') {
+            return [
+                'href' => $this->absolutizeForOpenGraph(trim($articleImage)),
+                'use_default_dimensions' => false,
+            ];
+        }
+
+        return $this->siteOgImage();
+    }
+
     /**
      * Crawlers require absolute https URLs; article/profile images are often https, //, or site-relative.
      */
diff --git a/src/Twig/NostrPathExtension.php b/src/Twig/NostrPathExtension.php
index 0d8a854..735b1e4 100644
--- a/src/Twig/NostrPathExtension.php
+++ b/src/Twig/NostrPathExtension.php
@@ -38,7 +38,7 @@ final class NostrPathExtension extends AbstractExtension
     }
 
     /**
-     * Lowercase 64-hex pubkey for {@see ArticleCardCoverExtension::articleOgImage} / card cover helpers.
+     * Lowercase 64-hex pubkey for {@see ArticleCardCoverExtension::articleCardCover} and article URLs.
      */
     public function pubkeyHexFromNpub(string $npub): string
     {
diff --git a/templates/base.html.twig b/templates/base.html.twig
index 245c59e..8819d10 100644
--- a/templates/base.html.twig
+++ b/templates/base.html.twig
@@ -39,8 +39,7 @@
     <link rel="manifest" href="{{ path('pwa_manifest') }}">
 
     {% block ogtags %}
-        {% set _pubkey_hex = pubkey_hex_from_npub(publisher_npub|default('')) %}
-        {% set _og = article_og_image(null, _pubkey_hex) %}
+        {% set _og = site_og_image() %}
         {% set _og_image = _og.href %}
         {% set _og_default_dims = _og.use_default_dimensions %}
         <meta property="og:type" content="website">
diff --git a/templates/home.html.twig b/templates/home.html.twig
index 9016c82..e3ac99c 100644
--- a/templates/home.html.twig
+++ b/templates/home.html.twig
@@ -7,8 +7,7 @@
 {% endblock %}
 
 {% block ogtags %}
-    {% set _pubkey_hex = pubkey_hex_from_npub(publisher_npub|default('')) %}
-    {% set _og = article_og_image(null, _pubkey_hex) %}
+    {% set _og = site_og_image() %}
     {% set _og_image = _og.href %}
     {% set _og_default_dims = _og.use_default_dimensions %}
     <link rel="canonical" href="{{ url('home') }}">
diff --git a/templates/pages/category.html.twig b/templates/pages/category.html.twig
index 2d69b7a..a8c363a 100644
--- a/templates/pages/category.html.twig
+++ b/templates/pages/category.html.twig
@@ -11,8 +11,7 @@
 {% block ogtags %}
     {% set _title = category.title|default('') %}
     {% set _summary = category.summary|default('')|striptags|u.truncate(159, '…') %}
-    {% set _pubkey_hex = pubkey_hex_from_npub(publisher_npub|default('')) %}
-    {% set _og = article_og_image(null, _pubkey_hex) %}
+    {% set _og = site_og_image() %}
     {% set _og_image = _og.href %}
     {% set _og_default_dims = _og.use_default_dimensions %}
     {% set _is_articles_route = app.request.attributes.get('_route') == 'articles' %}