We'll create fresh WordPress site with Get Json Api installed. You have 20 minutes to test the plugin after that site we'll be deleted.
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).
[getapi url="www.mysite.com" limit="5" type="[CYCLE or LIST]"]:
url: url before ?json=get_recent_posts
limit: number element of json result
type: “Cycle” is a slideshow of thumbs or “List” is the list of post titles