barryp

Sorry for the delay. After looking through the plugin code, there is a has_post_thumbnail option. I came up with this that I’m sure could be written better, I’m still learning.

// Check for Plugin
              if (class_exists('MultiPostThumbnails')) {

                // Set Thumbnail
                $thumb = MultiPostThumbnails::the_post_thumbnail(get_post_type(), 'preview-image');
                $has_thumb = MultiPostThumbnails::has_post_thumbnail(get_post_type(), 'preview-image', strval(get_the_ID()));

                // Thumbnail exist? Else show Not Found
                if ($has_thumb) : echo $thumb; else : echo '<img src="'. get_bloginfo('template_directory') . '/img/default_thumb.jpg" />'; endif;

                // Plugin not found.
              } else {

                echo "MultiPostThumbnails Not Found.";

              }

Let me know if this doesn’t work for you.

// Check for Plugin
if (class_exists('MultiPostThumbnails')) {

	// Set Thumbnail
	$thumb = MultiPostThumbnails::the_post_thumbnail(get_post_type(), 'preview-image');

	// Thumbnail exist? Else show Not Found
	if ($thumb) : echo $thumb; else : echo '<img src="url/to/default/image.jpg">'; endif;

	// Plugin not found.
	} else {

		echo "MultiPostThumbnails Not Found.";
}