Image spam is old news. The spammers use botnets to send uniquely modified images in each spam e-mail. The images have to be unique – otherwise spam filters could just simply drop known spam images.
So far, the images have typically been modified by adding colors, changing fonts, and inserting random dots and lines.
Results have typically looked like this (URLs smudged to prevent accidental business benefits for the spammers):
Over the last few days, we're seeing more image spam that is rendering the spam text with a pseudo 3D layout:
Generating images like this is of course more computing intensive… but hey, spammers have lots of computing power at their disposal via the huge botnets they're running. It's not like they couldn't afford to render unique 3D spam for every recipient.