fix: correct the Twitter Card in social share preview (#1498)

---------

Co-authored-by: Cotes Chung <[email protected]>

_includes/head.html

@@ -20,7 +20,7 @@
 
     {% unless src contains '://' %}
       {%- capture img_url -%}
-        {% include img-url.html src=src img_path=page.img_path %}
+        {% include img-url.html src=src img_path=page.img_path absolute=true %}
       {%- endcapture -%}
 
       {%- capture old_url -%}{{ src | absolute_url }}{%- endcapture -%}
@@ -31,15 +31,20 @@
 
   {% elsif site.social_preview_image %}
     {%- capture img_url -%}
-      {% include img-url.html src=site.social_preview_image %}
+      {% include img-url.html src=site.social_preview_image absolute=true %}
     {%- endcapture -%}
 
     {%- capture og_image -%}
       <meta property="og:image" content="{{ img_url }}" />
     {%- endcapture -%}
 
-    {% assign old_meta_clip = '<meta name="twitter:card"' %}
-    {% assign new_meta_clip = og_image | append: old_meta_clip %}
+    {%- capture twitter_image -%}
+      <meta property="twitter:card" content="summary_large_image" />
+      <meta property="twitter:image" content="{{ img_url }}" />
+    {%- endcapture -%}
+
+    {% assign old_meta_clip = '<meta name="twitter:card" content="summary" />' %}
+    {% assign new_meta_clip = og_image | append: twitter_image %}
     {% assign seo_tags = seo_tags | replace: old_meta_clip, new_meta_clip %}
   {% endif %}
 
@@ -85,7 +90,7 @@
   {% endif %}
 
   <!-- Bootstrap -->
-  <link rel="stylesheet" href="{{ site.data.origin[type].bootstrap.css | relative_url}}">
+  <link rel="stylesheet" href="{{ site.data.origin[type].bootstrap.css | relative_url }}">
 
   <!-- Font Awesome -->
   <link rel="stylesheet" href="{{ site.data.origin[type].fontawesome.css | relative_url }}">

_includes/img-url.html

@@ -2,8 +2,9 @@
   Generate image final URL based on `site.img_cdn`, `page.img_path`
 
   Arguments:
-    src - basic image path, required
-    img_path - relative path of image, optional
+    src - required, basic image path
+    img_path - optional, relative path of image
+    absolute - optional, boolean, if true, generate absolute URL
 
   Return:
     image URL
@@ -14,7 +15,7 @@
 {%- if url -%}
   {% unless url contains ':' %}
     {%- comment -%} CND URL {%- endcomment -%}
-    {% assign prefix = site.img_cdn | default: '' | relative_url %}
+    {% assign prefix = site.img_cdn | default: '' %}
 
     {%- comment -%} Add page image path prefix {%- endcomment -%}
     {% assign url = include.img_path | default: '' | append: '/' | append: url %}
@@ -26,6 +27,12 @@
       | replace: '//', '/'
       | replace: ':', ':/'
     %}
+
+    {% if include.absolute %}
+      {% assign url = url | absolute_url %}
+    {% else %}
+      {% assign url = url | relative_url %}
+    {% endif %}
   {% endunless %}
 {%- endif -%}