<?php

/**
 * Add image sizes to media UI
 *
 * Adds custom image sizes to the "Insert Media" user interface
 * and adds custom class to the `<img>` tag.
 *
 * @since  1.0.0
 * @access public
 * @param  array $sizes Gets the array of image size names.
 * @global array $_wp_additional_image_sizes Gets the array of custom image size names.
 * @return array $sizes Returns an array of image size names.
 */
function ccd_insert_custom_image_sizes( $sizes ) {

	// Access global variables.
	global $_wp_additional_image_sizes;

	// Return default sizes if no custom sizes.
	if ( empty( $_wp_additional_image_sizes ) ) {
		return $sizes;
	}

	// Capitalize custom image size names and remove hyphens.
	foreach ( $_wp_additional_image_sizes as $id => $data ) {

		if ( ! isset( $sizes[$id] ) ) {
			$sizes[$id] = ucwords( str_replace( [ '-', '_' ], ' ', $id ) );
		}
	}

	// Return the modified array of sizes.
	return $sizes;

}

// Add the operative filter.
add_filter( 'image_size_names_choose', 'ccd_insert_custom_image_sizes' );