functions.php

<?php


// unregister all default WP Widgets
    function unregister_default_wp_widgets() {
    unregister_widget('WP_Widget_Pages');
    unregister_widget('WP_Widget_Calendar');
    unregister_widget('WP_Widget_Archives');
    unregister_widget('WP_Widget_Links');
    unregister_widget('WP_Widget_Meta');
    unregister_widget('WP_Widget_Search');
    unregister_widget('WP_Widget_Text');
    unregister_widget('WP_Widget_Categories');
    unregister_widget('WP_Widget_Recent_Posts');
    unregister_widget('WP_Widget_Recent_Comments');
    unregister_widget('WP_Widget_RSS');
    unregister_widget('WP_Widget_Tag_Cloud');
    }
    add_action('widgets_init', 'unregister_default_wp_widgets', 1);


// set thumbnail size
    set_post_thumbnail_size( 130, 130, true ); // default Post Thumbnail dimensions (cropped)



?>