CSS - Center Image at all times - html

Question

I have an image that I am using inside a Div.
I was wondering how I could center the image both vertically and horizontally at all times.
At the moment, when I stretch it, it seems to be stretching from the top left corner, is there a way I could have it centered at all times.
I have searched the web and tried various things but can not seem to get it to work.
this is my html:
<div class="container"></div>
here is my css:
.container {
width: 100%;
height: 75vh;
background-image: url("http://i.stack.imgur.com/2OrtT.jpg");
background-size: cover;
background-repeat: no-repeat;
background-position: 50% 50%;
}
Any help or advice is appreciated, thank you in advance.
EDIT you can see that when I stretch the browser, it
seems to be stretching from the left, i want to be able to have the
Image centered so it stretches from all sides equally*

Answer 1

I got the solution..!
Here is your html file :
<div class="container"></div>
CSS file :
.container {
width: 100%;
height: 75vh;
position: absolute;
margin: auto;
background-image: url("http://i.stack.imgur.com/2OrtT.jpg");
background-size: cover;
background-repeat: no-repeat;
background-position: 50% 50%;
top: 0;
left: 0;}
Here is working demo

Answer 2

background-position: center will align your image in vertical and horizontal center.
Check below snippet:
* {
margin: 0;
padding: 0;
}
.container {
width: 100%;
height: 100vh;
background-image: url("http://i.stack.imgur.com/2OrtT.jpg");
background-repeat: no-repeat;
background-position: center;
}
<div class="container"></div>

Answer 3

.container {
width: 100%;
height: 75vh;
background-image: url("http://i.stack.imgur.com/2OrtT.jpg");
background-size: cover;
background-repeat: no-repeat;
background-position: center;
background-size:auto;
}
<div class="container"></div>

Answer 4

HTML :
<div class="container"></div>
CSS :
.container{width: 100%;height: 75vh;position: absolute;margin: auto;background-image: url("http://i.stack.imgur.com/2OrtT.jpg");background-size: cover;background-repeat: no-repeat;background-position: 50% 50%;top: 0;left: 0;}