Enable auto display images for Outlook for internal emails
Do you use Outlook? Is it connected to your Active Directory Domain? Follow these steps to automatically display images for Outlook (PC) internal recipients:
We need to add both http://*.yourdomain.com and https://*.yourdomain.com to the Site to Zone Assignment List for your domain.
Here's a blog post that covers the steps to make this change:Securing Zone Levels in Internet Explorer