function custom_taxonomy_shortcode($atts) {
    ob_start();

    $atts = shortcode_atts(
        array(
            'taxonomy' => 'opciones_estandar',
            'post_id' => get_the_ID()
        ),
        $atts
    );

    $terms = get_the_terms($atts['post_id'], $atts['taxonomy']);
    echo '<div class="taxonomy-group">';
    if ($terms) {
        foreach ($terms as $term) {
            echo '<div class="taxonomy-element">';
            $image = get_field('imagen_taxonomia', $atts['taxonomy'] . '_' . $term->term_id);
            if ($image) {
                $ancho_formato = get_field('ancho_formato', $atts['taxonomy'] . '_' . $term->term_id);
                $ancho_estilo = $ancho_formato ? ' style="width:' . esc_attr($ancho_formato * 2) . 'px;"' : '';
                echo '<img src="' . $image['url'] . '" alt="' . $term->name . '"' . $ancho_estilo . '>';
            }
            if (get_field('texto_a_mostrar', $atts['taxonomy'] . '_' . $term->term_id)) {
                echo '<p>' . get_field('texto_a_mostrar', $atts['taxonomy'] . '_' . $term->term_id) . '</p>';
            } else {
                echo '<p>' . $term->name . '</p>';
            }
            echo '</div>';
        }
    }
    echo '</div>';
    return ob_get_clean();
}
add_shortcode('custom_taxonomy', 'custom_taxonomy_shortcode');