最小限のマークアップ変更で目的の出力を実現するには:http://jsfiddle.net/pratik136/AzyQG
HTML:
<div class ="image-section">
<img class="tall" src ="http://static.guim.co.uk/sys-images/Lifeandhealth/Pix/pictures/2009/3/5/1236251569000/Six-gorgeous-plants-Close-001.jpg" width="60px" height="180px">
<img src ="http://static.guim.co.uk/sys-images/Lifeandhealth/Pix/pictures/2009/3/5/1236251569000/Six-gorgeous-plants-Close-001.jpg" width="120px" height="90px">
<img src ="http://static.guim.co.uk/sys-images/Lifeandhealth/Pix/pictures/2009/3/5/1236251569000/Six-gorgeous-plants-Close-001.jpg" width="120px" height="90px">
</div>
<div class ="image-section"></div>
CSS:
.tall {
float: right;
}
img {
float: left;
}
.image-section{
width: 180px;
}