Alan, it’s up to the browsers to support image formats other than GIF, JPG, PNG, etc. There’s nothing in the spec that defines a list of supported or unsupported formats. So, SVG should be a go, which would provide for more complex gradients.
J. King – that’s how I was thinking gradient would be defined. I think having gradient() apply to colors, or even borders, would be nice, and shouldn’t be forbidden by the spec. How do you (all of you) think gradient() would work in the background shorthand? Would it be used in place of url()? Could you combine the two? Could you only combine the two when using multiple backgrounds?