Delight Star Inc.

Jun'ya Hirano

Satoshi Maehira

Multiple Images Field is a plugin to add a filed that allows you to set multiple images to posts screen.
It becomes available by making the following settings from “Settings” and writing the function for Multiple Images Field on the theme template.
<ul>
<li>Enabled post types</li>
<li>Maximum image count</li>
<li>Whether to register the first image as a featured image.</li>
</ul>
Refer to the following help page for the use of functions. 
<a href="https://github.com/delight-star/multiple-images-field/wiki/How-to-Use" rel="nofollow ugc">https://github.com/delight-star/multiple-images-field/wiki/How-to-Use</a>

Multiple Images Field

Add a field for setting multiple images to posts screen.

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.

Multiple Images Field vs Multiple Post Thumbnails