It sounds like you need a transform:scale
HTML
<div class="box">
<img src="http://lorempixel.com/output/city-q-c-200-200-1.jpg" alt=""/>
</div>
CSS
.box {
width:250px;
height:250px;
padding:10px;
margin: 25px;
border:1px solid grey;;
}
img {
display: block;
transition:all 0.25s ease;
}
.box:hover img {
-webkit-transform:scale(1.25)
}