garousiv

Currently there is no featured_media image in WordPress json output with this plugin it is added to your WordPress kernel and you can also get featured_media image of each post
<h3>Arbitrary section</h3>
You may provide arbitrary sections, in the same format as the ones above. This may be of use for extremely complicated 
plugins where more information needs to be conveyed that doesn’t fit into the categories of “description” or 
“installation.” Arbitrary sections will be shown below the built-in sections outlined above.
<h3>A brief Markdown Example</h3>
Ordered list:
<ol>
<li>Some feature</li>
<li>Another feature</li>
<li>Something else about the plugin</li>
</ol>
Unordered list:
<ul>
<li>something</li>
<li>something else</li>
<li>third thing</li>
</ul>
Here’s a link to <a href="https://wordpress.org/" title="Your favorite software" rel="ugc">WordPress</a> and one to <a href="https://daringfireball.net/projects/markdown/syntax" title="Markdown is what the parser uses to process much of the readme file" rel="nofollow ugc">Markdown’s Syntax Documentation</a>. 
Titles are optional, naturally.
Markdown uses email style notation for blockquotes and I’ve been told:
<blockquote>
Asterisks for emphasis. Double it up for strong.
</blockquote>
<pre><code><?php code(); // goes in backticks ?>
</code></pre>

Add Image to Rest Api

With this plugin you can add the featured_media image property to the rest api

Formcrafts

Extends the functionality of <a href="https://wordpress.org/plugins/json-rest-api/" rel="ugc">WP REST API</a>. Allows you to request only certain fields.
Use &fields=ID,title to fetch only the ID and title. Works with posts, comments, taxonomy, media.

WP REST API Filter Fields

Extends the functionality of [WP REST API]. Allows you to request only certain fields.

Add Image to Rest Api vs WP REST API Filter Fields