Center image in div horizontally [duplicate]

Question

Every solution posted here assumes that you know the dimensions of your img, which is not a common scenario. Also, planting the dimensions into the solution is painful.

Simply set:

/* for the img inside your div */
display: block;
margin-left: auto;
margin-right: auto;

or

/* for the img inside your div */
display: block;
margin: 0 auto;

That's all.

Note, that you'll also have to set an initial min-width for your outer div.

text-align: center will only work for horizontal centering. For it to be in the complete center, vertical and horizontal you can do the following :

div
{
    position: relative;
}
div img
{
    position: absolute;
    top: 50%;
    left: 50%;
    margin-left: [-50% of your image's width];
    margin-top: [-50% of your image's height];
}

A very simple and elegant solution to this is provided by W3C. Simply use the margin:0 auto declaration as follows:

.top_image img { margin:0 auto; }

More information and examples from W3C.

<div class="outer">
    <div class="inner">
        <img src="http://1.bp.blogspot.com/_74so2YIdYpM/TEd09Hqrm6I/AAAAAAAAApY/rwGCm5_Tawg/s320/tall+copy.jpg" alt="tall image" />
    </div>
</div>
<hr />
<div class="outer">
    <div class="inner">
        <img src="http://www.5150studios.com.au/wp-content/uploads/2012/04/wide.jpg" alt="wide image" />
    </div>
</div>

CSS

img
{
    max-width: 100%;
    max-height: 100%;
    display: block;
    margin: auto auto;
}

.outer
{
    border: 1px solid #888;
    width: 100px;
    height: 100px;
}

.inner
{
    display:table-cell;
    height: 100px;
    width: 100px;
    vertical-align: middle;
}