image center absalute code example

Example 1: center image with position absolute

.wrapper img {
  left: 50%;
  transform: translate(-50%,0);
  position: absolute;
  z-index: 1 
}

Example 2: center an image horizontally and vertically

.center{
    margin: 0;
    position: absolute;
    top: 50%;
    left: 50%;
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
}