Losing images with https but not http

I've just installed a SSL cert on 3 of my domains in a multisite. When accessing the sites as https many of my images dissappear. In particular header and background images. Accessing as http they're still there. I've tried various setting of "force ssl" in domain mapping with no changes in results. Also I keep seeing references to the sub domain in my multisite which doesn't have a SSL attached to it. How can I eliminate the disappearing images?