Center image based on size inside div with whitespace - css

Question

I am jumping into a large complex application today and it's a bit daunting.
So, I want to solve the issue locally then find where the solution should eventually be located.
I have square images that come from sources of various sizes. Currently the image fills the div regardless of its dimensions.
<li class="hint-li" data-position="undefined" data-id="551ef3279934asda2e2565" id="551efsfasd8354582e2565" style="background-image: url(http://s3.amazonaws.com/source/558dadasd9a0f3.616asd74.jpg);">
<div class="sold-out hidden">
</div>
<div class="partnered hidden">
</div>
<div class="overlay">
<div class="row">
<div class="col">
<strong>
Thermal bath, aromatherapy, massage
</strong>
<em>
Aire Ancient Bath
</em>
<strong class="hintPrice">
$181
</strong>
</div>
</div>
</div>
<div class="options">
<div class="row">
<div class="col">
<a target="_blank" class="buy" href="http://www.ancientbathsny.com/aire-services/thermal-bath-with-aromatherapy-and-relaxing-30-minutes-massage/">
Buy
</a>
<a target="_blank" class="hint">
Hint
</a>
</div>
<div class="col">
<ul>
<li>
<a class="twitter" target="_blank">
<span class="sprite twitter-alt">
</span>
</a>
</li>
<li>
<a class="facebook" target="_blank">
<span class="sprite facebook-alt">
</span>
</a>
</li>
<li>
<a class="email">
<span class="sprite email">
</span>
</a>
</li>
</ul>
</div>
</div>
</div>
</li>
Here is the CSS that effects these image sizes:
.grid>ul>li {
width: 247px;
height: 250px;
background-position: center;
background-size: cover;
display: inline-block;
margin: 0 20px 20px 0;
position: relative;
vertical-align: top;
cursor: pointer;
-webkit-box-shadow: 1px 1px 1px 1px #ddd;
box-shadow: 1px 1px 1px 1px #ddd;
}
I'm trying to center the image within the div and have the remaining space be white space:
I have tried various approaches such as:
position: absolute;
margin: auto;
top: 0;
left: 0;
right: 0;
bottom: 0;
But it is breaking their format on the page.
How do I get the desired behavior?

Answer 1

As in this JS Fiddle these lines should be in your .grid>ul>li css:
background-position: center center;
background-repeat:no-repeat;
background-size: contain;
background-color:white;

Answer 2

EDIT: My answer is not actually applicable to OP, but I will leave it here in case someone is looking to center img elements as OP described in the title.
Wrap the following class around each img attribute:
.example-wrapper img {
text-align:center;
transform: translateY(-50%);
top: 50%;
height: auto;
max-width: 100%;
max-height:100%;
position: relative;
background-color: white;
}
extra option: "text-align:center;" above can be replaced with:
display: flex;
justify-content:center;
HTML
<div class="example-wrapper">
<img ....>
</div>