In days gone by, any time you opened an email in Outlook Express, the program automatically downloaded any and all images referenced in that message. Why? Because many emails are formatted in HTML, which is really just a "mapping" language. In effect, HTML tells the receiving application, "Retrieve this text and place it here; then retrieve these pictures and place them there."
This is great if you want to see the graphics the email sender has prepared for you. However, there's a potential problem here, too. Spammers figured out a way to exploit this behavior by using tiny, invisible pictures called "Web beacons" to determine whether their message reached a valid email address.
The solution: SP2 changes the behavior of Outlook Express to make sure that pictures are not automatically downloaded. You now must decide on a case-by-case basis whether to download an email's pictures.
And did you know that you can configure Outlook Express not to download messages automatically even without Service Pack 2. To do so, follow these steps: