digitalissimo

If you need to get the information from another site or your site using JSON API (https://wordpress.org/plugins/json-api/) you can use this plugin. 
For slideshow this plugin use Cycle2 (http://jquery.malsup.com/cycle2).
<h4>Shortcode</h4>
<pre><code>[getapi url="www.mysite.com" limit="5" type="[CYCLE or LIST]"]:
</code></pre>
<ul>
<li>
url: url before ?json=get_recent_posts
</li>
<li>
limit: number element of json result
</li>
<li>
type: “Cycle” is a slideshow of thumbs or “List” is the list of post titles
</li>
</ul>

Get Json Api

Retrieve the results of the API of a site that uses the plugin JSON API

arminmeth

While WordPress is slowly but surely becoming a complete application framework and JSON REST API is huge step in this direction, there is a large number of WordPress users that do not need advanced features like those offered by WordPress JSON REST API. This plugin helps them to turn those advanced features off and not worry about it.
While other similar plugins disable JSON REST API functionality only for anonymous users, Kill JSON REST API completely disables the framework for all users and removes links and tags from head element.

Kill JSON REST API

Completely disables JSON REST API for both registered and anonymous users in WordPress 4.7.* and removes API links and tags.

Get Json Api vs Kill JSON REST API