Den mig veterligt enklaste grunden för detta är
<style type="text/css">
<!--
#bildbox1{
width: 650px;
height: auto;
}
img{
padding: 5px;
float: left;
}
#bildbox2{
width: 170px;
height: auto;
}
-->
</style>
</head>
<body>
<div id="bildbox1"><p>
<img src="" width="150" height="150" alt="" /><img src="" width="150" height="150" alt="" /><img src="" width="150" height="150" alt="" />
<img src="" width="150" height="150" alt="" /><img src="" width="150" height="150" alt="" /><img src="" width="150" height="150" alt="" />
<img src="" width="150" height="150" alt="" /><img src="" width="150" height="150" alt="" /><img src="" width="150" height="150" alt="" />
<img src="" width="150" height="150" alt="" /><img src="" width="150" height="150" alt="" /><img src="" width="150" height="150" alt="" />
</p></div>
<div id="bildbox2"><p>
<img src="" width="150" height="150" alt="" /><img src="" width="150" height="150" alt="" /><img src="" width="150" height="150" alt="" />
<img src="" width="150" height="150" alt="" /><img src="" width="150" height="150" alt="" />
</p></div>
</body>
</html>
du behöver inte ha med height heller