.img-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  grid-auto-rows: 200px;
  grid-gap: 5px;
  padding: 5px;
  grid-auto-flow: dense;
}

.img-container img {
   width: 100%;
   height: 100%;
}

.horizontal{
    grid-column: span 2;
    grid-row: span 2;
}

.vertical {
    grid-row: span 3;
}

.big{
    grid-column: span 2;
    grid-row: span 2;
}

 ul {
    list-style-type: none;
    padding-left: 0; /* Also remove default left padding from ul */
}