Seth Carstens

sethmatics

Gallery plugin that’s simple because it leans on existing WordPress gallery features provided by http://sethmatics.com/.
NEW TO WORDPRESS? Please read about how the default gallery works at https://codex.wordpress.org/Gallery_Shortcode
We decided that the default gallery that WordPress builds is lacking some very simple features. 
Enhance your gallery’s without having to learn a completely new interface! Upload images as you 
normally would, insert the “gallery” tag as you normally would, with the plugin enabled BAAM! 
Your gallery is not in a beautiful showcase. Wait, don’t have room on your page for a showcase? 
No problem, we got you covered! Ad a simple attribute (modal) to the gallery code and define a 
thumbnail image… now you have a thumbnail that opens an overlay box on the page with your gallery showcase 
in it. No, it doesn’t navigate away from the current page, its very similar to a lightbox effect.
But wait, you want more you say? Oh you mean you use the featured image enhancement from WordPress? 
Good news, we even offer you the ability to link your featured image to your gallery showcase. It 
will cause the featured image, when clicked, to open the sexy overlay box for you. Snazzy!
Great…. so now I have to worry about 10 more javascript libraries on my page… Nope! The only 
scripts we are loading on the page are jQuery UI and small gallery plugin for jQuery. This means it 
shouldn’t conflict with any of your other site features. Well, if your not sold yet, just try it out 
and see for yourself how quick and easy it is to extend the gallery WordPress features.
Features include:
<ul>
<li>uses the existing WordPress gallery shortcode to keep inserting galleries easy and simple</li>
<li>tiny plugin, overhead media files and scripts are minimal</li>
<li>scripts optimized to be loaded at proper times to keep page load time down</li>
<li>extends featured images to link them to a gallery of your choosing</li>
<li>built as part of the SM plugins group which is being compiled to optimize page load speeds when using SM plugins together by minimizing files loaded on the site to 1 library. Stop loading 50 stylesheets and 39 javascript files, instead using the SM Plugins will pull from a single library and detect whats been loaded to keep you site load time down.</li>
</ul>
Features Coming in version 2, Next Version Updates:
<ul>
<li>javascript post-load images upon visibility to reduce page load time</li>
<li>modal box will load its contents with AJAX to reduce page load time even more</li>
<li>some styling options inside the wordpress interface (currently only available using CSS)</li>
<li>ability to select more plugin options while inserting the gallery from the WordPress media popup</li>
<li>ability to select an existing image from the media gallery for use as a gallery thumbnail image</li>
</ul>
Don’t forget to rate our plugin so we know how we are doing!

SM Gallery

Gallery plugin that's simple because it leans on existing WordPress gallery features provided by http://sethmatics.com/.

voceplatforms

Chris Scott

Adds multiple post thumbnails to a post type. If you’ve ever wanted more than one Featured Image on a post, this plugin is for you.

Multiple Post Thumbnails

Even though this plugin hasn't been updated in a long time, it still works great! So I guess there's just no reason for the developer to have it updated. ;-)
For me this plugin is one of the easiest ways to selectively add a header image. I want it on some pages, but not on others. Using the standard Featured Image function will set it foor all or none, so that's not flexible enough.
One suggestion for an update though:
Now you still need to add the following snippet to your theme's function.php.
if (class_exists('MultiPostThumbnails')) {
    new MultiPostThumbnails(
        array(
            'label' => 'Secondary Image',
            'id' => 'secondary-image',
            'post_type' => 'post'
            'post_type' => 'page'
        )
    );
}
It would be great if the plugin did this automatically. That will also keep the plugin active if you switch themes. 
P.S.
To add the meta box to other post types, just add it to the snippet.
'post_type' => 'event' will add it for Events Manager, for example. ;-)



Still works great!

Adds multiple post thumbnails to a post type. If you've ever wanted more than one Featured Image on a post, this plugin is for you.

SM Gallery vs Multiple Post Thumbnails