Works on 3.5.1

Here is the code I changed to line 87-104 of wp-thumbie.php to pull featured images instead of random image:

foreach($searches as $search) {
   $categorys = get_the_category($search->ID);	//Fetch categories of the plugin
   $featured_image = wp_get_attachment_image_src( get_post_thumbnail_id( $search->ID ), 'single-post-thumbnail' );
   $p_in_c = false;	// Variable to check if post exists in a particular category
   $title = trim(stripslashes($search->post_title));
   if ($crp_settings[display_post_text]) {
   $post_text = strip_tags($search->post_content);
   //$post_text = wp_trim_excerpt($post_text); // Get Post Ecerpt
   $post_text = truncate($post_text,$crp_settings[post_text_char]); // Get Post Excerpt
   }
   $image = ""; // Null Variable to verify for no image found case

   preg_match_all( '|<img.*?src=[\'"](.*?)[\'"].*?>|i', $search->post_content, $matches );
   if ( isset( $matches ) ) $image = $featured_image[0];

   if (strlen(trim($image))==0) {
   $image = $pluginDir.'images/default.png' ; // when no image found in post
   }