By enabling the option to "Block HTML graphics in email messages from being downloaded," all remotely stored images will be replaced with a small, blank image. To view the message with the original images, click the "Show HTML Graphics" link at the bottom of the message.

Why do I still see images in my mail?
Images that are sent as attachments will be shown in the attachments area, even with this option turned on. Also note that this option will not prevent images outside of the email messages from loading. Navigational, informational, and advertising images will still load normally.