Registering Custom Post Type images and Taxonomies

//Registering Custom Post Type images and taxonomies
add_action( 'init', 'register_themepost', 20 );
function register_themepost() {
    $labels = array(
        'name' => _x( 'images', 'my_custom_post','custom' ),
        'singular_name' => _x( 'Image', 'my_custom_post', 'custom' ),
        'add_new' => _x( 'Add New', 'my_custom_post', 'custom' ),
        'add_new_item' => _x( 'Add New ImagePost', 'my_custom_post', 'custom' ),
        'edit_item' => _x( 'Edit ImagePost', 'my_custom_post', 'custom' ),
        'new_item' => _x( 'New ImagePost', 'my_custom_post', 'custom' ),
        'view_item' => _x( 'View ImagePost', 'my_custom_post', 'custom' ),
        'search_items' => _x( 'Search ImagePosts', 'my_custom_post', 'custom' ),
        'not_found' => _x( 'No ImagePosts found', 'my_custom_post', 'custom' ),
        'not_found_in_trash' => _x( 'No ImagePosts found in Trash', 'my_custom_post', 'custom' ),
        'parent_item_colon' => _x( 'Parent ImagePost:', 'my_custom_post', 'custom' ),
        'menu_name' => _x( 'images Posts', 'my_custom_post', 'custom' ),
    );
    $args = array(
        'labels' => $labels,
        'hierarchical' => false,
        'description' => 'Custom Image Posts',
        'supports' => array( 'title', 'editor', 'excerpt', 'author', 'thumbnail', 'comments', 'revisions', 'post-formats', 'custom-fields' ),
        'taxonomies' => array( 'post_tag','image_categories'),
        'show_ui' => true,
        'show_in_menu' => true,
        'menu_position' => 5,
        'menu_icon' => get_stylesheet_directory_uri() . '/functions/panel/images/catchinternet-small.png',
        'show_in_nav_menus' => true,
        'publicly_queryable' => true,
        'exclude_from_search' => false,
        'query_var' => true,
        'can_export' => true,
        'rewrite' => array('slug' => 'images/image_categories','with_front' => FALSE), // rewrite url of post
        'public' => true,
        'has_archive' => 'images',
        'capability_type' => 'post'
    ); 
    register_post_type( 'images', $args );//max 20 charachter cannot contain capital letters and spaces
} 

function images_taxonomy() { 
    register_taxonomy( 
        'image_categories',  //The name of the taxonomy. Name should be in slug form (must not contain capital letters or spaces).
        'images',        //post type name
        array( 
            'hierarchical' => true, 
            'label' => 'Categories',  //Display name
            'query_var' => true,
            'rewrite' => array(
                'slug' => 'categories', // This controls the base slug that will display before each term
                'with_front' => false // Don't display the category base before
            )
        ) 
    ); 
} 
add_action( 'init', 'images_taxonomy');