You can apply up to 4 image layers in a profile, giving you heaps of creative freedom. Use them for watermarks, decorative effects, lomo-style effects and other uses for which you might otherwise have used Photoshop.
Designate each layer independently as 'watermark.n'. Where n is 0, 1, 2, or 3. The image to the right has 3 image layers - in the top left (holly), bottom right (holly rotated) and over the whole image (snow).
The two holly images are the same - the bottom right one has been rotated 180 degrees. It also has a text layer thrown in for good measure. The code for the image on the right is:
When referencing images in the URL, use the HTML encoding character '%2F' to represent the '/' character.