Image spam, a plague on email right now, continues to get more and more creative.
For the most part, the images are embedded in the email, although sometimes they’re sent as a hyplink (an email client like Outlook can show images in the email when formatted in HTML, either through a hyperlink or as an embedded image, a technique that also works with RTF through OLE embedding).
Some people may wonder why the images are getting all odd looking, with slashes and odd text and the like. That’s largely to bypass OCR filters (for example, SpamAssassin uses an OCR plug-in to detect image spam). It’s also to continually change the checksum on the image.
Expect much more creativity as the spammers continue to try to get through the filters.