Methods for enhancing e-mail messages to provide preview enhanced e-mail messages that allow e-mail senders to associate customized preview content related to an e-mail message, including graphical images, that can be viewed by recipients directly from an e-mail inbox listing without opening the e-mail message itself. The e-mail messages have associated preview instructions, and have a preview trigger that upon actuation opens a temporary preview window on the inbox view and displays the preview content in accordance with the preview instructions while the preview trigger is actuated. The invention is applicable to web-based e-mail systems as well as to POP-based and proprietary e-mail systems.