Make WordPress image insert function use html5 figures

gistfile1.php

/**
 * Swap Default TinyMCE Tags for Figure Tags on Images
 */
function html5_insert_image( $html, $id, $caption, $title, $align ) {


    $title   = esc_attr( $title );
    $caption = sanitize_text_field( $caption );
    $id      = absint( $id );
    $url     = esc_url( wp_get_attachment_url( $id ) );
    $align   = esc_attr( $align );

    // check to see if we have a caption
    if ( trim( $caption ) != '' ) {
        $caption_class = ' wp-caption';
    }


    $html5 = '<figure id="post-' . $id . ' media-' . $id . '" class="align-' . $align . $caption_class . ' post-img">';

    $html5 .= '<img src="' . $url . '" alt="' . $title . '" class="wp-post-image">';

    if ( trim( $caption ) != '' ) {
        $html5 .= '<figcaption class="wp-caption-text">' . $caption . '</figcaption>';
    }
    $html5 .= '</figure>';
    return $html5;
}
add_filter( 'image_send_to_editor', 'html5_insert_image', 10, 9 );