set post thumb (req. taxonomy-images plugin) (wordpress)

        /*
         * IF NO POST THUMB IS SET ON POST (EVENEMANG) SAVE, USE TAXONOMY IMAGE (requires taxonomy-images plugin)
         *
         */
        function check_for_taxonomy_images_plugin() {
            if(is_plugin_active('taxonomy-images/taxonomy-images.php')) {
                add_action('save_post', 'set_post_thumb', 10, 2);
            }
        }
        add_action('admin_init', 'check_for_taxonomy_images_plugin' );
        function set_post_thumb($post_id) {
            $event_type_id = 0;
            if(!wp_is_post_revision($post_id)) {
                $post_type = get_post_type($post_id);
                $post_thumb = get_post_thumbnail_id($post_id);
                if($post_type == 'evenemang' && !$post_thumb) {
                     $event_types = get_the_terms($post_id, 'evenemangstyp'); // get terms associated with the post
                     //$event_type_id = $event_types[0]->term_id; // get id of the first returned term
                       $event_type_id = $event_types[0]->term_taxonomy_id;
                         $tax_images = get_option('taxonomy_image_plugin'); // get TIP options
                     if(!empty($tax_images)) {
                        $defaultimage = $tax_images[$event_type_id];
                        set_post_thumbnail($post_id,$defaultimage);
                    }
                } // end $post_type === 'evenemang'
            }
        }