I'm attempting to use the line-height method to v-align an image within a div.
I do not understand why it's not working.
This method has been gone over multiple times on StackOverflow.
If you simply replace the img with text, the text v-aligns without problem.
<div class="image_wrapper">
    <img src="http://requestaweb.com/wp-content/uploads/2014/05/css.png">
</div>
.image_wrapper {
    height: 400px;
    line-height: 400px;
    vertical-align: middle;
    background-color: gray;
    text-align: center;
}
img {
    height: 200px;
}
 
     
    