//CUSTOMIZE POST TYPE MANGEMENT COLUMNS
add_action( 'manage_posts_custom_column' , 'custom_columns' );

add_filter('manage_edit-attachment_columns' , 'set_edit_attachment_columns');
function set_edit_mediapage_columns($columns) {
	return array_merge($columns, array(
		'imagetype' => __('Media Category')
		)
	);
}

function custom_columns( $column ) {
	global $post;
	
	switch ( $column ) {
		case 'imagetype':
			$imagetype_meta_values = get_the_terms($post->ID, 'imagetype');
			foreach($imagetype_meta_values as $imagetype_meta_value) {
				$value .= $imagetype_meta_value->name.', ';
			}
			if (is_string($value)) {
				echo $value;
			}
			break;
	}
}

///MEDIA CATEGORY SUBMENU///
add_action('admin_menu', 'my_plugin_menu');

function my_plugin_menu() {
	add_media_page('Media Category', 'Media Category', 'read', 'imagetype', 'display_media_taxonomy_page');
}

function display_media_taxonomy_page() {
	$args = array(
		'tax_query' => array(
			array(
				'taxonomy' => 'imagetype',
				'field' => 'slug'
			)
		)
	);
	
	$myquery = new WP_QUERY($args);
	
	while (have_posts() ) : thepost();
		echo get_the_term_list( $post->ID, 'imagetype', '', ', ', '' );
		echo '<p>BLARG'.the_title().'</p>';
	endwhile;
	
	wp_reset_postdata();
}