.container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  justify-items: center;
  grid-gap: 0;
}

.item {
  width: 100%;
  overflow: hidden;
  background: #000;
}

img {
  opacity: 1;
  width: 100%;
  height: 100%;
  transform: scale(1.15);
  transition: transform 0.5s, opacity 0.5s;
}

.mailimg {
  opacity: 1;
  width: 50px;
  height: 50px;
  transform: none;
  transition: none;
}

img:hover {
  opacity: 1;
  transform: scale(1.03);
}