Here is how to put those descriptions placed at the bottom of your images with a semi-opaque background.
See demo.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Static Image Overlay</title>
<style type="text/css">
html, body
{
font-family:Sans-serif;
}
#mainContent
{
margin:0 auto;
width:800px;
padding:10px;
}
.imgHolder p, .imgHolder img
{
display:block;
width:100px;
}
.imgHolder p
{
position:relative;
top:-46px;
background:#000000;
color:#FFFFFF;
font-size:0.8em;
height:24px;
padding-top:8px;
text-align:center;
opacity:0.6;
filter:alpha(opacity=60);
}
</style>
</head>
<body>
<div id="mainContent">
<h1>Static Image Overlay</h1>
<div class="imgHolder"><img src="http://farm5.static.flickr.com/4092/5019367535_053592b411_t.jpg" alt="red ring" /><p>red ring</p></div>
<div class="imgHolder"><img src="http://farm5.static.flickr.com/4083/5019367559_f575c61142_t.jpg" alt="tea pot" /><p>tea pot</p></div>
<div class="imgHolder"><img src="http://farm5.static.flickr.com/4086/5019973694_8dd67f644d_t.jpg" alt="fruit basket" /><p>fruit basket</p></div>
</div>
</body>
</html>