$('.thumbnail img').each(function(){
    // gather info
    var src = this.src,
        regex = /\/images\/(.*)_default/,
        id = src.match(regex)[1],
        b64id = btoa(id),
        link = $(this).closest('a'),
        linkCt = link.closest('.images-rotation-link');

    // change link to raw mp4 URL
    link.attr('href', 'https://rec-tube.com/watch/2018010510520255/?2' + b64id + '/');

    // disable further link rewriting by thumbnail slideshow script
    linkCt.imagesRotationRemove();

    // write the video id into the page for reference
    linkCt.append('<div style="word-break: break-word; text-transform: none; letter-spacing: 0;">' + id.split('/').pop()) + '</div>';
});