Envira Gallery tweak

envira-gallery-tweak.php

<?php

add_action( 'envira_gallery_api_config', 'tgm_envira_disable_fancybox_preloading' );
function tgm_envira_disable_fancybox_preloading() {
    ob_start();
    ?>
    preload: 0,
    nextEffect: 'none',
    prevEffect: 'none',
    <?php
    echo ob_get_clean();
}