.portfolio-item {
  height: 360px;
  overflow: hidden;
}

.portfolio_thumb {
  height: 100%;
  overflow: hidden;
  position: relative;
}

.portfolio_thumb img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: contain;
  transform: translateY(0%);
  transition: none;
}

.portfolio-item:hover .portfolio_thumb img {
  animation: scrollImage 4s linear forwards;
}

@keyframes scrollImage {
  0% {
    transform: translateY(0%);
  }

  100% {
    transform: translateY(-40%);
  }
}