'float' issue

This is a bit junior - sorry , I am just getting my head around css instead of tables and have been battling through a site to do so.

www.dslproductions.co.uk/devsite/projects.php

I have an issue with images on this page if viewed in firefox - I think its the float command - basically in ie the div stretches down to fit the image floating in it, in firefox it doesn't - can anyone help me? css code below

pis are -

.profilepic {
float: left;
margin-right: 20px;
margin-bottom: 20px;
clear: all;
}

div they are in is -

.infoboxconts {
width: 500px;
margin-left: 20px;
margin-bottom: 10px;
background-color: #29016A;
border-left: 1px #8D54D7 solid;
border-right: 1px #8D54D7 solid;
border-bottom: 1px #8D54D7 solid;
padding: 10px;
}