What's that from? Outlook express?
edit: nevermind, I found it's from xxx. I'll be posting a report on this soon, let me do some sleuthing
edit2: Just curious, was the email mostly graphics with little to no text?
edit3: Basically, Hotmail is seeing it as spam, and marking it as such; basically saying it could be dangerous to visit the links listed in the email. It goes further by not displaying the images.
Most web based free email services do the same by not showing the images, because that is actually one way spammers can confirm that your email address is indeed active, so they can add it to their list of "working" addresses.
Displaying the images in known spam emails is just as bad as using a "remove" link in the spam itself.