Nick Halsey

This plugin creates a fullscreen slideshow that displays randomly-selected pictures from your media library. Designed to display pictures related to your business/organization in the background at an event or in your office, there is no need to configure any settings or controls. Image captions/descriptions are automatically displayed as well, and can be configured based on your needs.
Once activated, you can view the slideshow by visiting <code>http://yourdomain.com/slideshow</code>. All JPEG images will be displayed (since .jpg is best for pictures, while .png and .gif are typically used for graphics).
Please note that it is not currently possible to pause the slideshow or go back; the slideshow is not designed for personal viewing. However, clicking/tapping on the image will open its attachment page in a new tab, allowing images to be contextualized or edited easily.
The slideshow can also be embedded into your site via a widget or a shortcode.
You can control some options by adjusting the url of the slideshow. Parameters are controlled via query string (and widget options and shortcode attributes).
<ul>
<li><code>size</code> is the size of the image to load, either <code>thumbnail</code> (discouraged), <code>medium</code>, <code>large</code>, <code>full</code>, or <code>auto</code>, which uses medium or large depending on <code>wp_is_mobile()</code>.</li>
<li><code>year</code> is the 4-digit numeric year in which the images were published.</li>
<li><code>month</code> is the numeric month in which the images were published (between 1 and 12), typically but not necessarily used in conjunction with <code>year</code>.</li>
<li><code>mode</code> defines a subset of images to use, such as <code>featured</code> for featured images only.</li>
<li><code>captions</code> controls the captions display: either <code>auto</code>, <code>none</code>, <code>title</code>, <code>titlecaption</code>, <code>caption</code>, or <code>description</code>. Caption data is read from the image attachment post and can be updated in the media library.</li>
</ul>
Using all options, for example: 
http://example.com/slideshow?size=full&year=2014&month=4&mode=featured&captions=titlecaption
You can see it in action <a href="http://uscasce.com/slideshow" rel="nofollow ugc">here</a>.

Content Slideshow

This plugin creates a fullscreen slideshow that displays randomly-selected pictures from your media library. Designed to display pictures related to y …

Willy Bahuaud

This plugin add a metabox which allox to upload and link multiple images to one post. 
Pictures are linked by the way of meta_value (and attachments ID). They can be reordered using drag and drop.
Number of allowed pictures and concerned post types can be overited using hooks.
Plugin includes many functions to retrieve linked pictures. 
For more information on using the plugin, refer to the section <a href="/extend/plugins/multi-image-metabox/other_notes/" rel="nofollow ugc">“Other Notes”</a>.
<h3>Set concerned post types</h3>
Paste this into your theme’s functions.php file :
 
<h3>Set allowed number of picts</h3>
Paste this into your theme’s functions.php file : 
 ‘_image1’, 
 ‘image2’ => ‘_image2’, 
 ); 
 return $picts; 
 } 
 ?>
<h4>Set allowed number of picts, depending to the post_type</h4>
Paste this into your theme’s functions.php file : 
 add_filter(‘list_images’,’my_list_images’,10,2); 
 function my_list_images($list_images, $cpt){ 
 global $typenow; 
 if($typenow == “my_custom_post_type” || $cpt == “my_custom_post_type”) 
 $picts = array( 
 ‘image1’ => ‘_image1’, 
 ‘image2’ => ‘_image2’, 
 ‘image3’ => ‘_image3’, 
 ); 
 else 
 $picts = array( 
 ‘image1’ => ‘_image1’, 
 ‘image2’ => ‘_image2’, 
 ‘image3’ => ‘_image3’, 
 ‘image4’ => ‘_image4’, 
 ‘image5’ => ‘_image5’, 
 ‘image6’ => ‘_image6’, 
 ‘image7’ => ‘_image7’, 
 ‘image8’ => ‘_image8’, 
 ); 
 return $picts; 
 }
<h3>get_images_ids()</h3>
This function have to be used into a template file, or any function. 
It return an array of the linked attachments’s ID.
It take two arguments whose are :
<ol>
<li>include the thumbnail ? (boolean) if true include the thumbnail in the returned datas</li>
<li>
ID (integer) for targeting images linked to a specific post
 45, 
 ‘image1’ => 5, 
 ‘image2’ => 6, 
 ‘image3’ => 12, 
 ‘image6’ => 20, 
 ‘image7’ => 15 
);
//Empty pictures ar not returned
?>
<h3>get_images_src()</h3>
This function have to be used into a template file, or any function. 
It return an array of URIs and dimension for the linked attachments’s, by order.
</li>
</ol>
It take three agruments whose are :
<ol>
<li>size (string) the size to return</li>
<li>include the thumbnail ? (boolean) if true include the thumbnail in the returned datas</li>
<li>
ID (integer) for targeting images linked to a specific post
 array( 
 [0] => ‘http://url_of_the_medium_pict.jpg’, 
 [1] => 340, 
 [2] => 200, 
 [3] => false //I’ve no idea what is it… 
 ), 
 ‘image2’ => array( 
 [0] => ‘http://url_of_the_medium_second_pict.jpg’, 
 [1] => 340, 
 [2] => 200, 
 [3] => false //I’ve no idea what is it… 
 ) 
);
?>
<h3>get_multi_images_src()</h3>
Same as get_image_src(), but return two sizes for all the pictures.
</li>
</ol>
It take for agruments whose are :
<ol>
<li>size (string) the size to return</li>
<li>size2 (string) another size to return</li>
<li>include the thumbnail ? (boolean) if true include the thumbnail in the returned datas</li>
<li>
ID (integer) for targeting images linked to a specific post
 array( 
 [0] => array( 
 [0] => ‘http://url_of_the_medium_pict.jpg’, 
 [1] => 340, 
 [2] => 200, 
 [3] => false //I’ve no idea what is it… 
 ), 
 [1] => array( 
 [0] => ‘http://url_of_the_full_pict.jpg’, 
 [1] => 1020, 
 [2] => 600, 
 [3] => false //I’ve no idea what is it… 
 ), 
 ), 
 ‘image2’ => array( 
 [0] => array( 
 [0] => ‘http://url_of_the_medium_second_pict.jpg’, 
 [1] => 340, 
 [2] => 200, 
 [3] => false //I’ve no idea what is it… 
 ), 
 [1] => array( 
 [0] => ‘http://url_of_the_second_full_pict.jpg’, 
 [1] => 1020, 
 [2] => 600, 
 [3] => false //I’ve no idea what is it… 
 ) 
 ) 
); 
//Empty pictures ar not returned
?></li>
</ol>

Multi Image Metabox

Add a multi-image metabox to your posts, pages and custom post types

Content Slideshow vs Multi Image Metabox