{% macro seo_metadata(article) %}
<meta property="og:title" content="{{ article.title|striptags }} {%if article.subtitle %} - {{ article.subtitle }} {% endif %}"/>
<meta property="og:type" content="article" />
<meta property="og:url" content="{{ SITEURL }}/{{ article.url }}" />
<meta property="og:description" content="{{article.summary|striptags}}" />
<meta property="og:site_name" content="{{ SITENAME|striptags }}" />
<meta property="og:article:author" content="{{ article.author }}" />
{% if article.date %}
<meta property="og:article:published_time" content="{{ article.date.isoformat() }}" />
{% endif %}
{% if article.locale_modified and article.modified %}
<meta property="" content="{{ article.modified.isoformat() }}" />
{% endif %}
<meta name="twitter:card" content="summary">
{% from '_includes/_defaults.html' import TWITTER_USERNAME with context %}
{%if TWITTER_USERNAME %}
<meta name="twitter:creator" content="@{{TWITTER_USERNAME}}">
{% endif %}
<meta name="twitter:title" content="{{ article.title|striptags }} {%if article.subtitle %} - {{ article.subtitle }} {% endif %}">
<meta name="twitter:description" content="{{article.summary|striptags}}">
{% endmacro %}


{% macro seo_metadata(article) %}
<meta property="og:title" content="{{ article.title|striptags }} {%if article.subtitle %} - {{ article.subtitle }} {% endif %}"/>
<meta property="og:type" content="article" />
<meta property="og:url" content="{{ SITEURL }}/{{ article.url }}" />
<meta property="og:description" content="{{article.summary|striptags}}" />
<meta property="og:site_name" content="{{ SITENAME|striptags }}" />
<meta property="og:article:author" content="{{ article.author }}" />
{% if article.date %}
<meta property="og:article:published_time" content="{{ article.date.isoformat() }}" />
{% endif %}
{% if article.locale_modified and article.modified %}
<meta property="" content="{{ article.modified.isoformat() }}" />
{% endif %}
<meta name="twitter:card" content="summary">
{% from '_includes/_defaults.html' import TWITTER_USERNAME with context %}
{%if TWITTER_USERNAME %}
<meta name="twitter:creator" content="@{{TWITTER_USERNAME}}">
{% endif %}
<meta name="twitter:title" content="{{ article.title|striptags }} {%if article.subtitle %} - {{ article.subtitle }} {% endif %}">
<meta name="twitter:description" content="{{article.summary|striptags}}">
{% if article.social_media_image %}
<meta property="og:image" content="{{article.social_media_image}}" />
<meta name="twitter:image" content="{{article.social_media_image}}" >
{% endif %}
{% endmacro %}


Add support for og:image and twitter:image using article.social_media_image
Add support for og:image and twitter:image using article.social_media_image

Update #15
