Featured Image for Shopify Blog

featured_image_shopify_blog.liquid

<!-- upload an image named blog_id111111.jpg, where the number is the ID of your blog post (in the URL) -->
<ul class="blogs">
{% for article in blog.articles %}
            {% capture tn_img %}blog_id{{ article.id }}.jpg{% endcapture %}
            <li class="entry clearfix">
                <p class="byline">
                    {% if article.tags.size > 0 %}
                    {% for tag in article.tags limit 1 %} 
                    <span class="tag">{{ tag }}</span>
                    {% endfor %}
                    {% endif %}
                    <time class="updated" datetime="{{ article.published_at | date: "%Y-%m-%dT%H:%M:%S%Z" }}" pubdate>{{ article.published_at | date: "%B %d, %Y" }}</time>
                </p>  
                <a href="{{ article.url }}">
                    <span class="text">
                        <h5>{{ article.title }}</h5>
                        <div class="excerpt">{{ article.excerpt }}</div>
                    </span>
                    <img alt="{{ article.title }}" src="{{ tn_img | asset_url }}" />
                </a>
            </li>
{% endfor %}
</ul>