Quick workaround:
The admin part works, the output not. After looking at the code of the plugin I decided it was less work to code some output myself.
The data is stored in the post meta table, so, in the loop…:
<?php
$meta_value = get_post_meta( $post->ID, 'post_second-image_thumbnail_id', true);
$image = wp_get_attachment_image_src( $meta_value, 'full' );
if ( $image[1] >= 778 ) :
echo '<img src="' .$image[0]. '" id='top-image' style="width: 778px; height: '.$image[2].'px"/>';
endif;
?>
This code is for the second-image I defined in functions.php
The meta_key for this is: post_second-image_thumbnail_id
In this case the image is the full image and the width is hardcoded to 778 pixels, you can set these values to your own needs, like:
<?php
$meta_value = get_post_meta( $post->ID, 'post_third-image_thumbnail_id', true);
$image = wp_get_attachment_image_src( $meta_value, 'medium' );
echo '<img src="' .$image[0]. '" style="width:'.$image[1].'px"; height: '.$image[2].'px"/>';
?>