gistfile1.txt

const opacity = 0.4;

const current = document.querySelector("#current");

const [maxHeight, maxWidth] = [current.height, current.width];

const imgs = document.querySelectorAll(".imgs img");

imgs[0].style.opacity = opacity;

function imgClick(e) {
  // reset opacity for all images
  imgs.forEach(img => {
    img.style.opacity = 1;
  });

  const newImg = e.target;
  current.src = newImg.src;
  current.height = maxHeight;
  current.width = maxWidth;

  current.classList.add("fade-in");

  setTimeout(() => {
    current.classList.remove("fade-in");
  }, 500);
  e.target.style.opacity = opacity;
}

imgs.forEach(img => img.addEventListener("click", imgClick));