Dragoon Apps

A featured image is an important part of a blog post, and it can be tough to choose the right one. This plugin makes it easy to select the first uploaded image as the featured image for your post. You can save time by using this plugin, and you won’t have to worry about choosing the wrong image.
With this plugin, it will automatically set the first uploaded image in a pos as its featured image. This will help you save time and ensure that your posts look great..
You can enable this feature for each post type in Settings > TL Auto Feature Image

TL Auto Feature Image

Automatically set the first uploaded image of a post as the featured image.

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.

TL Auto Feature Image vs Multiple Post Thumbnails