function custom_add_attribute_thumbnail_field( $term ) {
    $thumbnail_id = get_term_meta( $term->term_id, '_thumbnail_id', true );
    $image_url = wp_get_attachment_image_url( $thumbnail_id, 'thumbnail' ); // Imposta la dimensione dell'immagine desiderata (esempio: 'thumbnail', 'medium', 'large')
    ?>
    <tr class="form-field">
        <th scope="row" valign="top"><label for="attribute_thumbnail"><?php esc_html_e( 'Attribute Thumbnail', 'text-domain' ); ?></label></th>
        <td>
            <div id="attribute_thumbnail_preview">
                <?php if ( $image_url ) : ?>
                    <img src="<?php echo esc_url( $image_url ); ?>" alt="<?php echo esc_attr( $term->name ); ?>" style="max-width:100px; max-height:100px;">
                <?php endif; ?>
            </div>
            <input type="hidden" id="attribute_thumbnail" name="attribute_thumbnail" value="<?php echo esc_attr( $thumbnail_id ); ?>">
            <button type="button" id="upload_attribute_thumbnail_button" class="button"><?php esc_html_e( 'Upload/Add image', 'text-domain' ); ?></button>
            <button type="button" id="remove_attribute_thumbnail_button" class="button"><?php esc_html_e( 'Remove image', 'text-domain' ); ?></button>
            <script>
                jQuery(document).ready(function($) {
                    // Carica l'immagine
                    $('#upload_attribute_thumbnail_button').click(function() {
                        var custom_uploader = wp.media({
                            title: '<?php esc_html_e( "Choose or Upload Image", "text-domain" ); ?>',
                            button: {
                                text: '<?php esc_html_e( "Use Image", "text-domain" ); ?>'
                            },
                            multiple: false
                        }).on('select', function() {
                            var attachment = custom_uploader.state().get('selection').first().toJSON();
                            $('#attribute_thumbnail').val(attachment.id);
                            $('#attribute_thumbnail_preview').html('<img src="' + attachment.url + '" alt="<?php echo esc_attr( $term->name ); ?>" style="max-width:100px; max-height:100px;">');
                        }).open();
                    });

                    // Rimuovi l'immagine
                    $('#remove_attribute_thumbnail_button').click(function() {
                        $('#attribute_thumbnail').val('');
                        $('#attribute_thumbnail_preview').html('');
                    });
                });
            </script>
            <p class="description"><?php esc_html_e( 'Upload or select an image to set as the attribute thumbnail.', 'text-domain' ); ?></p>
        </td>
    </tr>
    <?php
}
add_action( 'pa_attributo_add_form_fields', 'custom_add_attribute_thumbnail_field', 10, 2 );
add_action( 'pa_attributo_edit_form_fields', 'custom_add_attribute_thumbnail_field', 10, 2 );

function custom_save_attribute_thumbnail( $term_id ) {
    if ( isset( $_POST['attribute_thumbnail'] ) ) {
        $thumbnail_id = absint( $_POST['attribute_thumbnail'] );
        update_term_meta( $term_id, '_thumbnail_id', $thumbnail_id );
    }
}
add_action( 'edited_pa_attributo', 'custom_save_attribute_thumbnail', 10, 2 );