Having a hover or mouseover effect in views for drupal 7
You can do a simple thing like this:

HTML

&lt;a class="person" href="#"&gt;
   &lt;img src="" width="100" height="100"&gt;
   &lt;span&gt;John Doe&lt;/span&gt;
&lt;/a&gt;


CSS

a.person {
    border: 1px solid #ddd;
    display: block;
    height: 100px;
    overflow: hidden;
    width: 100px;
}
a.person:hover img {
    display: none;
}
a.person span {
    display: block;
    text-align: center;
    margin: 20% 0 0;
}


Fiddle:
http://jsfiddle.net/fXnmr/

If you want fade effects etc you need to go the Javascript/jQuery route.