One Crayon

Markup to Featured Image will automatically generate a featured image when you publish a post, with the intent of allowing you to publish posts with featured images from third-party clients like MarsEdit.
To add a featured image to your post, include one of the following markup variants in your post’s content:
<pre><code><img src="/path/to/image.jpg" data-featured-image="keep" />
<img src="/path/to/image.jpg" data-featured-image="strip" />

</code></pre>
If you use an <code><img></code> element, the values of the <code>data-featured-image</code> attribute specify whether the image should be displayed when the post is shown on your site (<code>keep</code>) or ignored when the post is displayed (<code>strip</code>). The order of attributes in your <code><img></code> tag (and whether you include other attributes, like width/height, title, alt, etc.) doesn’t matter. You can make it as complicated or simple as you like.
If the post already has a featured image, the plugin will do nothing (version 1.0 does not allow updating the thumbnail by updating the markup).

Markup to Featured Image

Automatically set the featured image (formerly the post thumbnail) for a post based on custom markup in the body text.

Kudratullah

Niamul

AbsolutePlugins

With Absolute Thumbnail Column you can upload, select or change post thumbnail (Aka Featured Image) with ease. No need to edit your page/post only just to change the thumbnail. It supports post types that have thumbnail supports.
Absolute Thumbnail Column is fully compatible with WooCommerce, integrates nicely with Image Column, and enabling uploading, selecting or changing product thumbnail from the list-table itself, saving a lot of time.
Absolute Thumbnail Column uses the native WordPress media popup, ensuring the security and integrity of core features of the media library.
<h3>Features</h3>
<ol>
<li>Unlimited Usages.</li>
<li>Supports all post type that has <code>thumbnail</code> support.</li>
<li>Builtin WooCommerce support.</li>
<li>Uses the native WordPress media popup.</li>
</ol>

Absolute Thumbnail Column

Absolute Thumbnail column allows you to upload, select and change thumbnail on any post-types right from the post table.

Markup to Featured Image vs Absolute Thumbnail Column