Is flash supported in themes

I’m trying to set up a flash-made menu for my blog. What I had as a simple top background JPG in my CSS coding, I am now trying to switch to a SWF which has the background and the menu altogether. But, as I refresh the blog after the change, it simply loads nothing in the stead of the SWF. I’ve scoured the web to find and answer but all I get is people trying to upload flash video content into blog posts. Obviously, what I want is to be able to use flash in the very blog “skeleton”, so to speak. So the question basically is, does WP.org self-hosted blogs support flash as used in their themes? At least it doesn’t seem to do so straight-of, I mean that it seems JPG and SWF is not interchangeable. But is there any plugin which would allow for this use? Or perhaps the error is in my CSS coding.

Anyway, I would appreciate any light on the subject. And thanks in advance for the support.