Since you have an image, there are services that will make your key from that
I had one done off an ebay seller (not for a BMW) and the process worked (the service in this instance was for a fold-out key and the cutting from image was an option)
Do a google search or just search ebay
e.g. http://www.keysfast.info/
If you try that route, I'd suggest the picture of the actual key, and not the tracing....