Incoming mail within Outlook 2000

Probably an obvious solution but has so far eluded me ! The company I have recently started working for have an Exchange 2000 mail server with Outlook 2000 as a front end. We have noted that certain incoming mail contains embeded objects such as pictures/logo’s. When mail has been recieved all embeded objects are retrieved on-line causing additional telephone bills.The sender of the mail specifies the source as HTML and ‘send pictures from the internet’. How can this be blocked ? I do not thinkthis is an Exchange issue but more so Outlook but cannot see any properties within the application to block this . Hope this makes sense and any feedback will be appreciated.