Blocking Remote Images in Thunderbird 2

In Thunderbird 2, the blocking of remote image to protect privacy is active by default. Sometimes this could be annoying. To change this behavior, you should use "advanced configuration" which is located at "General" tab of "Advanced" section in option dialog. At that dialog,

1. Click "Config Edit..." button, then a new dailog would pop up.
2. Fill in "remote" in "Filter" textbox and you could see "mailnews.message_display.disable_remote_image" preference which is set to true.
3. Double click the above preference, and it would change to false.