cover image will automatically be used as a thumbnail unless a thumbnail is explicitly provided. thumbnail can also be disabled

README.md

@@ -129,7 +129,7 @@ Parameter   | Description
 title       | Page or blog post title
 subtitle    | Short description of page or blog post that goes under the title
 tags        | List of tags to categorize the post. Separate the tags with commas and place them inside square brackets. Example: `[personal, analysis, finance]`
-cover-img   | Include a large full-width image at the top of the page.  You can either give the path to a single image, or provide a list of images to cycle through (see [my personal website](https://deanattali.com/) as an example).
+cover-img   | Include a large full-width image at the top of the page. You can either provide the path to a single image (eg. `"/path/to/img"`) , or a list of images to cycle through (eg. `["/path/img1", "/path/img2"]`). The first image will also be used as the thumbnail in the feed page. If you want to add a caption to an image, then the image should be provided as `{"/path/to/img" : "Caption of image"}`.
 comments    | If you want do add comments to a specific page, use `comments: true`. Comments only work if you enable one of the comments providers (Facebook, disqus, staticman, utterances) in `_config.yml` file. Comments are automatically enabled on blog posts but not on other pages; to turn comments off for a specific post, use `comments: false`. 
 
 ## Less commonly used parameters
@@ -140,7 +140,7 @@ Parameter   | Description
 ----------- | -----------
 readtime    | If you want a post to show how many minutes it will take to read it, use `readtime: true`.
 show-avatar | If you have an avatar configured in the `_config.yml` but you want to turn it off on a specific page, use `show-avatar: false`.
-thumbnail-img | For blog posts, if you want to add a thumbnail that'll show up next to the post's excerpt in the feed, use `thumbnail-img: /path/to/image`.
+thumbnail-img | For blog posts, if you want to add a thumbnail that'll show up next to the post's excerpt in the feed, use `thumbnail-img: /path/to/image`. You can use `thumbnail-img: ""` to disable a thumbnail.
 share-img   | If you want to specify an image to use when sharing the page on Facebook or Twitter, then provide the image's path or full URL here.
 social-share | By default, every blog post has buttons to share the page on social media. If you want to turn this feature off, use `social-share: false`.
 nav-short   | By default, the navigation bar gets shorter after scrolling down the page. If you want the navigation bar to always be short on a certain page, use `nav-short: true` 

_layouts/home.html

@@ -25,10 +25,23 @@ layout: page
     </p>
 
     <div class="post-entry-container">
+      {%- capture thumbnail -%}
         {% if post.thumbnail-img %}
+          {{ post.thumbnail-img }}
+        {% elsif post.cover-img %}
+          {% if post.cover-img.first %}
+            {{ post.cover-img[0].first.first }}
+          {% else %}
+            {{ post.cover-img }}
+          {% endif %}
+        {% else %}
+        {% endif %}
+      {% endcapture %}
+      {% assign thumbnail=thumbnail | strip %}
+      {% if thumbnail != "" %}
       <div class="post-image">
         <a href="{{ post.url | relative_url }}">
-          <img src="{{ post.thumbnail-img | relative_url }}">
+          <img src="{{ thumbnail | relative_url }}">
         </a>
       </div>
       {% endif %}

_posts/2020-02-26-flake-it-till-you-make-it.md

@@ -3,7 +3,7 @@ layout: post
 title: Flake it till you make it
 subtitle: Excerpt from Soulshaping by Jeff Brown
 cover-img: /assets/img/path.jpg
-thumbnail-img: /assets/img/path.jpg
+thumbnail-img: "/assets/img/thumb.png"
 share-img: /assets/img/path.jpg
 tags: [books, test]
 ---