Feature: OG Social media cards

Not Original Gangsta, but ObjectGraph

Reason: images were showing on LinkedIn, but small.

blogex/lib/blogex/post.ex

@@ -28,6 +28,7 @@ defmodule Blogex.Post do
     :description,
     :date,
     :blog,
+    :image,
     tags: [],
     published: true
   ]
@@ -39,6 +40,7 @@ defmodule Blogex.Post do
           body: String.t(),
           description: String.t(),
           date: Date.t(),
+          image: String.t() | nil,
           tags: [String.t()],
           blog: atom(),
           published: boolean()

blogex/lib/blogex/seo.ex

@@ -3,11 +3,33 @@ defmodule Blogex.SEO do
   SEO helpers for generating meta tags and sitemaps.
   """
 
+  @doc """
+  Returns a map of meta tag attributes for a blog listing page.
+  Useful for setting OpenGraph and Twitter card tags on blog index pages.
+
+      <meta property="og:title" content={@meta.og_title} />
+  """
+  def meta_tags_for_blog(blog_module, base_url) do
+    url = "#{base_url}#{blog_module.base_path()}"
+
+    %{
+      title: blog_module.title(),
+      description: blog_module.description(),
+      og_title: blog_module.title(),
+      og_description: blog_module.description(),
+      og_type: "website",
+      og_url: url,
+      og_image: nil,
+      twitter_card: "summary"
+    }
+  end
+
   @doc """
   Returns a map of meta tag attributes for a post.
   Useful for setting OpenGraph and Twitter card tags in your layout.
 
       <meta property="og:title" content={@meta.og_title} />
+      <meta property="og:image" content={@meta.og_image} />
   """
   def meta_tags(post, base_url, blog_module) do
     url = "#{base_url}#{blog_module.base_path()}/#{post.id}"
@@ -19,6 +41,7 @@ defmodule Blogex.SEO do
       og_description: post.description,
       og_type: "article",
       og_url: url,
+      og_image: if(post.image, do: "#{base_url}#{post.image}", else: nil),
       article_published_time: Date.to_iso8601(post.date),
       article_author: post.author,
       article_tags: post.tags,

blogex/test/blogex/post_test.exs

@@ -58,6 +58,20 @@ defmodule Blogex.PostTest do
 
       assert post.published == false
     end
+
+    test "preserves image from frontmatter" do
+      attrs = Map.put(valid_attrs(), :image, "/images/cover.png")
+
+      post = Post.build("x/2026/01-01-x.md", attrs, "<p>x</p>")
+
+      assert post.image == "/images/cover.png"
+    end
+
+    test "defaults image to nil when not in frontmatter" do
+      post = Post.build("x/2026/01-01-x.md", valid_attrs(), "<p>x</p>")
+
+      assert post.image == nil
+    end
   end
 
   defp valid_attrs do

blogex/test/blogex/seo_test.exs

@@ -6,6 +6,8 @@ defmodule Blogex.SEOTest do
 
   defmodule StubBlog do
     def base_path, do: "/blog/eng"
+    def title, do: "Engineering Blog"
+    def description, do: "Our engineering insights"
   end
 
   @base_url "https://example.com"
@@ -38,6 +40,63 @@ defmodule Blogex.SEOTest do
       assert meta.article_published_time == "2026-06-15"
       assert meta.article_tags == ["a", "b"]
     end
+
+    test "includes og_image when post has an image" do
+      post = build(image: "/images/cover.png")
+
+      meta = SEO.meta_tags(post, @base_url, StubBlog)
+
+      assert meta.og_image == "https://example.com/images/cover.png"
+    end
+
+    test "og_image is nil when post has no image" do
+      post = build()
+
+      meta = SEO.meta_tags(post, @base_url, StubBlog)
+
+      assert meta.og_image == nil
+    end
+
+    test "og_image uses absolute URL with base_url prefix" do
+      post = build(image: "/assets/post-hero.jpg")
+
+      meta = SEO.meta_tags(post, "https://myapp.dev", StubBlog)
+
+      assert meta.og_image == "https://myapp.dev/assets/post-hero.jpg"
+    end
+  end
+
+  describe "meta_tags_for_blog/2" do
+    test "returns website type" do
+      meta = SEO.meta_tags_for_blog(StubBlog, @base_url)
+
+      assert meta.og_type == "website"
+    end
+
+    test "includes blog title and description" do
+      meta = SEO.meta_tags_for_blog(StubBlog, @base_url)
+
+      assert meta.og_title == "Engineering Blog"
+      assert meta.og_description == "Our engineering insights"
+    end
+
+    test "has no og_image for blog listing" do
+      meta = SEO.meta_tags_for_blog(StubBlog, @base_url)
+
+      assert meta.og_image == nil
+    end
+
+    test "builds correct blog URL" do
+      meta = SEO.meta_tags_for_blog(StubBlog, @base_url)
+
+      assert meta.og_url == "https://example.com/blog/eng"
+    end
+
+    test "uses summary twitter card for blog listing" do
+      meta = SEO.meta_tags_for_blog(StubBlog, @base_url)
+
+      assert meta.twitter_card == "summary"
+    end
   end
 
   describe "sitemap/2" do