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).
Shortcode
[getapi url="www.mysite.com" limit="5" type="[CYCLE or LIST]"]:
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url: url before ?json=get_recent_posts
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limit: number element of json result
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type: 「Cycle」 is a slideshow of thumbs or 「List」 is the list of post titles
