Katsushi Kawamori

<h4>Set a featured image for post by a category</h4>
<ul>
<li>Bulk set the featured image of all the posts, when setting the category featured image.</li>
<li>If there are multiple categories, the parent category featured image takes precedence.</li>
<li>Can apply a category featured image to the post featured image, when posting.</li>
<li>Supports Custom Post Types.</li>
</ul>
<h4>Warning</h4>
<ul>
<li>Pressing the “Update” button after “Add New Image” or “Replace Image” under “Edit Category” will change the featured image for all posts in that category.</li>
<li>Even if you do not set an image, pressing the “Update” button under “Edit Category” will remove the featured image for all posts in that category.</li>
<li>If you do not need this feature, do not use this plugin !</li>
</ul>


Category Featured Image

Set a featured image for post by a category.

voceplatforms

Chris Scott

<p>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.</p>


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.

Category Featured Image vs Multiple Post Thumbnails