Whilst the answer by @HeXanon is great, it may not be ideal to turn off the pane, especially if you find the pane useful.
Another way, which is less intrusive, is to just ensure the details don't get back to the "spammer", which is what I think you're worried about.
Click the File tab.
Click Trust Center.
Under Microsoft Outlook Trust Center, click Trust Center Settings.
[Un]Check the Don't download pictures automatically in HTML e-mail messages or RSS items check box.