Create a custom post type in WordPress (called Press) with Featured Image option included

functions.php

<?php
// Create custom press posts
add_action( 'init', 'create_posttype' );
add_theme_support('post-thumbnails'); 
add_post_type_support( 'press', 'thumbnail' );  // Add Featured Image for Press Posts
function create_posttype() {
    register_post_type( 'press',
	array(
	    'labels' => array(
		'name' => __( 'Press' ),
		'singular_name' => __( 'Press' )
	    ),
	    'public' => true,
	    'has_archive' => true,
	    'rewrite' => array('slug' => 'press'),
	)
    );
}