By default Outlook will block images in HTML formatted email until you allow them to be downloaded.

This is due to possible malicious code that may be included.

Here is how to always accept images from trusted senders.

Beginner: Make Outlook Always Display Images in Emails from Trusted Senders

To download the images once, right-hit the message and select Download Pictures.

After that the pictures for the email will be displayed, where in this case its the Twitter logo.

This way all future messages from that sender will be displayed automatically.

sshot-2010-08-26-[04-30-13]

Of course you want to use your best judgment when always allowing images.

This way you dont have to take the extra step of downloading the pictures every time.

sshot-2010-08-26-[04-12-55]

sshot-2010-08-26-[04-29-30]

sshot-2010-08-26-[04-31-46]