Trouble using with image size and attribute with a class in it

[immeasurablespectacle]

I am trying to add a class to the post thumbnails but when I add the class it doesn't display the thumbnail. This also happens with the image size and I'm wondering if I'm doing something wrong. I have 2 post thumbnails ID "banner-image" and ID "right-small-image"

In the function.php file I have:

add_theme_support( 'post-thumbnails'  );
add_image_size('slider-background', '975', '345', true);
add_image_size('right-small', '250', '200');
add_image_size('wide-banner', '600', '200');

if (class_exists('MultiPostThumbnails')) {
    new MultiPostThumbnails(
        array(
            'label' => 'Top Banner Image',
            'id' => 'banner-image',
            'post_type' => 'page'
        )
    );

    new MultiPostThumbnails(
        array(
            'label' => 'Top Right Small Image',
            'id' => 'right-small-image',
            'post_type' => 'page'
        )
    );
}

In the page itself I have the code to display the two post thumbnail types:

    <?php
        // If the page has a banner image display it here
         if (class_exists('MultiPostThumbnails')) :
            $attr = array("class" => "banner-feature-image");
            MultiPostThumbnails::the_post_thumbnail(
                get_post_type(),
                "banner-image",
                "wide-banner",
                $attr
            );
        endif; 
    ?>

    <?php
        // If the page has a small right image on the top, beneath the heading, display it here
         if (class_exists('MultiPostThumbnails')) :
            $attr = array("class" => "right-small-feature-image");
            MultiPostThumbnails::the_post_thumbnail(
                get_post_type(),
                "right-small-image",
                "right-small",
                $attr
            );
        endif; 
    ?>

Is there some sort of issue with my syntax? Or is there some sort of bug?

It works just fine when I exclude the image size and the $attr at the end. When I include either of these the image stops showing up in the page and html output.

Thank you for making this incredibly useful plugin and for your time and consideration.

[chrisscott]

You're missing the post_id as the 3rd parameter in the call to MultiPostThumbnails::the_post_thumbnail(). See the function declaration or the docs for more info.

[immeasurablespectacle]

That fixed it, thanks!