Today was an interesting day as far as spam goes. Normally when we see a stock pump-and-dump campaign, it will be in a single form, whether that is stock in a text/plain message, or in an attached image.
Today on the other hand we saw 4 different variations of the same stock ticker SREA being pushed out at the same time. They were in text/plain format, attached jpeg/gif images, and one of the newer methods, PDF format.
All the images are highly randomized not only in width and height, but also in text, colours, and random pixels added throughout the images. PDF files seems to be a more recent spam trend and in this campaign they're simply taking the randomized images and embedding them in the PDF files.