I can't see images in a message
When you open new messages, some images may not appear immediately. Gmail disables images to protect you from unknown senders, like spammers, who use images and links to verify that your email address is real.
i think it's blocked by default to prevent spammers from knowing your address exists. if you view an image it will show on their server logs that you are real.
edit: just found confirmation of this....
http://support.google.com/mail/answer/8833?hl=en
Utter stupidity. It's much more effort to add people to the trusted list than click the spam button.
LOL. If you like spam, get a Yahoo mail account.
Gmail rocks, always one step ahead!