DJRavine

Updates the above code to work on the latest version of wordpress.
Just copy/paste into the functions.php and edit as required.
Allows the plugin to update as per normal without affecting the custom images used.

// WP Post Ratings Override plugin images, from plugin source
	function my_deregister_script() {
		$postratings_max = intval(get_option('postratings_max'));
		$postratings_ajax_style = get_option('postratings_ajax_style');
		$postratings_custom = intval(get_option('postratings_customrating'));
		if($postratings_custom) {
			for($i = 1; $i <= $postratings_max; $i++) {
				$postratings_javascript .= 'var ratings_'.$i.'_mouseover_image=new Image();ratings_'.$i.'_mouseover_image.src=ratingsL10n.plugin_url+"/images/"+ratingsL10n.image+"/rating_'.$i.'_over."+ratingsL10n.image_ext;';
			}
		} else {
			$postratings_javascript = 'var ratings_mouseover_image=new Image();ratings_mouseover_image.src=ratingsL10n.plugin_url+"/images/"+ratingsL10n.image+"/rating_over."+ratingsL10n.image_ext;';
		}
		wp_deregister_script( 'wp-postratings' );
		wp_enqueue_script('wp-postratings', plugins_url('wp-postratings/postratings-js.js'), array('jquery'), WP_POSTRATINGS_VERSION, true);
		wp_localize_script('wp-postratings', 'ratingsL10n', array(
			'plugin_url' => get_bloginfo('stylesheet_directory') . '/img/ratings',
			'ajax_url' => admin_url('admin-ajax.php'),
			'text_wait' => __('Please rate only 1 post at a time.', 'wp-postratings'),
			'image' => get_option('postratings_image'),
			'image_ext' => 'gif',
			'max' => $postratings_max,
			'show_loading' => intval($postratings_ajax_style['loading']),
			'show_fading' => intval($postratings_ajax_style['fading']),
			'custom' => $postratings_custom,
			'l10n_print_after' => $postratings_javascript
		));
	}
	add_action( 'wp_print_scripts', 'my_deregister_script', 100 );
	// Fixing WP-Ratings plugin initial output, to match Design
	function prefix_ratings_fix($html) {
		$search = plugins_url( '/wp-postratings/images/stars/' );
		$replace = get_bloginfo('stylesheet_directory') . '/img/ratings/images/stars/';

		$html = str_replace($search, $replace, $html);

		return $html;
	}
	add_filter( 'expand_ratings_template', 'prefix_ratings_fix', 999, 1 ); // WP-Ratings Filter