Many websites offer the flexibility to display the same page via both SSL and HTTP. The major problem with offering this is the possibility that embedded content will not be served via the same protocol; many browsers will throw an error if an SSL page embeds HTTP images.
However, there is a simple and W3C valid solution to this problem. Simply omit the protocol and colon from the URL:
The drawback to doing this everywhere is that you must be conscious as to whether the resource you are linking to is available on both SSL and HTTPS. Embedded scripts from services like Google Analytics are well served by this technique. If your enterprise uses a dedicated image hosting server, this is also a highly appropriate solution.