body {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr) );
  gap: 20px;
  margin: 20px;
  background: linear-gradient( blue, deeppink);
}

figure {
  margin: 0;
  aspect-ratio: 3/4;
}
img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}