These something new in the image-spam wave: pretty colours! This spammer is working hard to randomize his images and avoid OCR. Here's a sample:
And to give you an idea of the randomization here's another:
Thanks to Nick FitzGerald and Sorin Mustaca for samples. Notice how the letters are misaligned both vertically and horizontally to try to avoid OCR, and the background polygons are randomized. Also the aspect ratio and size of the messages have been changed for each image.