Answers for "align image in container"

center with css

.parent {
  position: relative;
}
.child {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

position images in center of container

.image-container {
    width: 500px;
    height: 500px;
    position: relative;
}

.image-container img {
    position: absolute;
    right: 0;
    left: 0;
    top: 0;
    bottom: 0;
    margin: auto auto;
}