Look out, Outlook: Gmail adds in-line images
Found on CNet News on Thursday, 09 April 2009

Gmail's got a new option in its labs section that lets users insert images directly into their e-mails, and not just as attachments. This has been something you've been able to do in standard e-mail software for ages, but Gmail's way of handling them for the last five years has simply been to stick them on as attachments that show up in the bottom of your outgoing message.
Sweet, now spammers can track GMail users with inline images too. Displaying inline images is one of the first options I disable in my E-Mail client.