<div >
<a href="ton lien">
<img src="images/ton_image.jpg" alt="image" class="grand" />
</a>
</div>
a .grand
{
display: block;
position: absolute;
width: 0px;
}
a:hover .grand
{
position: absolute;
top: 30px;
left: 100px;
width: auto;
height: auto;
}