mRWiNeT, нагуглил такой вариант :
Изображение всплывает при наведении, но не по центру (+/-)
.thumbnail {
position: relative;
z-index: 0;
}
.thumbnail:hover {
background-color: transparent;
z-index: 50;
}
.thumbnail span {
position: absolute;
background-color: #3d3d3d;
padding: 5px;
left: -1000px;
border: 1px solid white;
visibility: hidden;
color: Yellow;
text-decoration: none;
border-radius: 4px 4px 4px 4px;
-moz-border-radius: 4px 4px 4px 4px;
-webkit-border-radius: 4px 4px 4px 4px;
}
.thumbnail span img {
border-width: 0;
padding: 2px;
}
.thumbnail:hover span {
visibility: visible;
top: 0;
left: 60px;
}<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<link rel="stylesheet" href="style.css" />
<title></title>
</head>
<body>
<a class="thumbnail" href="#">
<img src="http://johncms.com/images/logo.gif" width="100px" height="66px" border="0" />
<span><img src="http://johncms.com/images/logo.gif" />Ваш текст</span>
</a>
</body>
</html>