You can achieve this with this simple CSS/HTML:
.image-container {
position: relative;
width: 200px;
height: 300px;
}
.image-container .after {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
display: none;
color: #FFF;
}
.image-container:hover .after {
display: block;
background: rgba(0, 0, 0, .6);
}
HTML
<div class="image-container">
<img src="http://lorempixel.com/300/200" />
<div class="after">This is some content</div>
</div>
Demo: http://jsfiddle.net/6Mt3Q/
UPD: Here is one nice final demo with some extra stylings.
.image-container {
position: relative;
display: inline-block;
}
.image-container img {display: block;}
.image-container .after {
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
display: none;
color: #FFF;
}
.image-container:hover .after {
display: block;
background: rgba(0, 0, 0, .6);
}
.image-container .after .content {
position: absolute;
bottom: 0;
font-family: Arial;
text-align: center;
width: 100%;
box-sizing: border-box;
padding: 5px;
}
.image-container .after .zoom {
color: #DDD;
font-size: 48px;
position: absolute;
top: 50%;
left: 50%;
margin: -30px 0 0 -19px;
height: 50px;
width: 45px;
cursor: pointer;
}
.image-container .after .zoom:hover {
color: #FFF;
}<link href="https://netdna.bootstrapcdn.com/font-awesome/4.0.3/css/font-awesome.min.css" rel="stylesheet"/>
<div class="image-container">
<img src="http://lorempixel.com/300/180" />
<div class="after">
<span class="content">This is some content. It can be long and span several lines.</span>
<span class="zoom">
<i class="fa fa-search"></i>
</span>
</div>
</div>