img {
max-width:100%;
height:auto;
##vertical-align: top;
}



<div id="conteneur_img_test">
<img src="image.jpg" id="img_test1">
</div>

<!--[if IE]>
<style type="text/css">
img {
width:expression(document.getElementById('conteneur_img_test').offsetWidth > document.getElementById('img_test').offsetWidth? document.getElementById('img_test').offsetWidth+"px" : "100%" ); 
}
</style>
<![endif]-->





#logo img {
  vertical-align: top;
}