diff --git a/src/Twig/NostrPathExtension.php b/src/Twig/NostrPathExtension.php
index de83b31..0d8a854 100644
--- a/src/Twig/NostrPathExtension.php
+++ b/src/Twig/NostrPathExtension.php
@@ -5,7 +5,9 @@ declare(strict_types=1);
 namespace App\Twig;
 
 use App\Entity\Article;
+use App\Service\NostrKeyHelper;
 use App\Service\NostrPathHelper;
+use Throwable;
 use Twig\Extension\AbstractExtension;
 use Twig\TwigFunction;
 
@@ -13,6 +15,7 @@ final class NostrPathExtension extends AbstractExtension
 {
     public function __construct(
         private readonly NostrPathHelper $nostrPathHelper,
+        private readonly NostrKeyHelper $nostrKeyHelper,
     ) {
     }
 
@@ -20,6 +23,7 @@ final class NostrPathExtension extends AbstractExtension
     {
         return [
             new TwigFunction('npub_from_hex', $this->npubFromHex(...)),
+            new TwigFunction('pubkey_hex_from_npub', $this->pubkeyHexFromNpub(...)),
             new TwigFunction('article_path', $this->articlePath(...)),
         ];
     }
@@ -33,6 +37,27 @@ final class NostrPathExtension extends AbstractExtension
         return $this->nostrPathHelper->npubFromPubkeyHex($pubkeyHex);
     }
 
+    /**
+     * Lowercase 64-hex pubkey for {@see ArticleCardCoverExtension::articleOgImage} / card cover helpers.
+     */
+    public function pubkeyHexFromNpub(string $npub): string
+    {
+        $n = trim($npub);
+        if ($n === '') {
+            return '';
+        }
+        try {
+            $hex = $this->nostrKeyHelper->convertToHex($n);
+            if (64 !== \strlen($hex) || !ctype_xdigit($hex)) {
+                return '';
+            }
+
+            return strtolower($hex);
+        } catch (Throwable) {
+            return '';
+        }
+    }
+
     public function articlePath(Article $article): string
     {
         return $this->nostrPathHelper->articlePath($article);
diff --git a/templates/base.html.twig b/templates/base.html.twig
index 96ed545..245c59e 100644
--- a/templates/base.html.twig
+++ b/templates/base.html.twig
@@ -39,9 +39,20 @@
     <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_image = _og.href %}
+        {% set _og_default_dims = _og.use_default_dimensions %}
         <meta property="og:type" content="website">
         <meta property="og:description" content="{{ website_description|e('html_attr') }}">
-        <meta property="og:image" content="{{ absolute_url(asset('og-image.jpg'))|e('html_attr') }}">
+        <meta property="og:image" content="{{ _og_image|e('html_attr') }}">
+        {% if _og_image starts with 'https://' %}
+            <meta property="og:image:secure_url" content="{{ _og_image|e('html_attr') }}">
+        {% endif %}
+        {% if _og_default_dims %}
+            <meta property="og:image:width" content="1200">
+            <meta property="og:image:height" content="630">
+        {% endif %}
         <meta property="og:site_name" content="{{ website_name|e('html_attr') }}">
     {% endblock %}
     {% block javascripts %}
diff --git a/templates/home.html.twig b/templates/home.html.twig
index d0e0694..0085bfe 100644
--- a/templates/home.html.twig
+++ b/templates/home.html.twig
@@ -7,7 +7,10 @@
 {% endblock %}
 
 {% block ogtags %}
-    {% set _og_image = absolute_url(asset('og-image.jpg')) %}
+    {% set _pubkey_hex = pubkey_hex_from_npub(publisher_npub|default('')) %}
+    {% set _og = article_og_image(null, _pubkey_hex) %}
+    {% set _og_image = _og.href %}
+    {% set _og_default_dims = _og.use_default_dimensions %}
     <link rel="canonical" href="{{ url('home') }}">
     <link rel="alternate" type="application/atom+xml" title="{{ website_name|e('html_attr') }} — all articles" href="{{ url('feed_magazine') }}">
     <meta property="og:type" content="website">
@@ -15,6 +18,13 @@
     <meta property="og:title" content="{{ website_name|e('html_attr') }}">
     <meta property="og:description" content="{{ website_description|e('html_attr') }}">
     <meta property="og:image" content="{{ _og_image|e('html_attr') }}">
+    {% if _og_image starts with 'https://' %}
+        <meta property="og:image:secure_url" content="{{ _og_image|e('html_attr') }}">
+    {% endif %}
+    {% if _og_default_dims %}
+        <meta property="og:image:width" content="1200">
+        <meta property="og:image:height" content="630">
+    {% endif %}
     <meta property="og:site_name" content="{{ website_name|e('html_attr') }}">
     <meta name="twitter:card" content="summary_large_image">
     <meta name="twitter:title" content="{{ website_name|e('html_attr') }}">
diff --git a/templates/pages/category.html.twig b/templates/pages/category.html.twig
index 0b45293..2d69b7a 100644
--- a/templates/pages/category.html.twig
+++ b/templates/pages/category.html.twig
@@ -11,7 +11,10 @@
 {% block ogtags %}
     {% set _title = category.title|default('') %}
     {% set _summary = category.summary|default('')|striptags|u.truncate(159, '…') %}
-    {% set _og_image = absolute_url(asset('og-image.jpg')) %}
+    {% set _pubkey_hex = pubkey_hex_from_npub(publisher_npub|default('')) %}
+    {% set _og = article_og_image(null, _pubkey_hex) %}
+    {% set _og_image = _og.href %}
+    {% set _og_default_dims = _og.use_default_dimensions %}
     {% set _is_articles_route = app.request.attributes.get('_route') == 'articles' %}
     {% set _is_category_route = app.request.attributes.get('_route') == 'magazine-category' %}
     {% set _articles_page = app.request.query.getInt('page', 1) %}
@@ -30,6 +33,13 @@
     <meta property="og:url" content="{{ _canonical_url }}">
     <meta property="og:description" content="{{ (_summary != '' ? _summary : _title)|e('html_attr') }}">
     <meta property="og:image" content="{{ _og_image|e('html_attr') }}">
+    {% if _og_image starts with 'https://' %}
+        <meta property="og:image:secure_url" content="{{ _og_image|e('html_attr') }}">
+    {% endif %}
+    {% if _og_default_dims %}
+        <meta property="og:image:width" content="1200">
+        <meta property="og:image:height" content="630">
+    {% endif %}
     <meta property="og:site_name" content="{{ website_name|e('html_attr') }}">
     <link rel="canonical" href="{{ _canonical_url }}">
     <meta name="twitter:card" content="summary_large_image">