How to center align vertically and horizontally inside a div?

Consider an example given below,

<div class="container"><img src=""></div>

To center the image inside this div,

.container{
position: relative;
display: inline-block;
text-align: center;
}

img{    
    max-height: 100%;
    max-width: 100%;
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    margin: auto;
}