bridget/assets/js/theme.js

const images = document.getElementsByClassName("image");

let globalIndex = 0,
    last = {x: 0, y: 0};

const activate = (image, x, y) => {
    image.style.left = `${x}px`;
    image.style.top = `${y}px`;
    image.style.zIndex = globalIndex;

    image.dataset.status = "active";

    last = {x, y};
}

const distanceFromLast = (x, y) => {
    return Math.hypot(x - last.x, y - last.y);
}

const handleOnMove = e => {
    if (distanceFromLast(e.clientX, e.clientY) > (window.innerWidth / 20)) {
        const lead = images[globalIndex % images.length],
            tail = images[(globalIndex - 5) % images.length];

        activate(lead, e.clientX, e.clientY);

        if (tail) tail.dataset.status = "inactive";

        globalIndex++;
    }
}

window.onmousemove = e => handleOnMove(e);

window.ontouchmove = e => handleOnMove(e.touches[0]);