Kate,
That is sounding like a viable solution but I don't know how to isolate the DWF so the preview is that and that alone, not the other line work too. Otherwise, the preview doesn't show enough detail to see what the drawing is. I will experiment a bit and see if this approach works.
Dean,
Our web site does not, NOT use the windows embedded preview. When you click on the file in the directory tree you are actually getting a preview of the drawing as it appears, sorta like how a print preview gets created. It is not the last saved "picture". This preview or "print preview" is created in the AutoDESK DWF Viewer, not through the DWG file or windows. Thanks for your thought though.