Holy fuck, don't!
Don't copy data around that you don't own, you will break stuff badly! Just alone fucking up the linked list is bad, but copying opaque pointer around... Why are you advising people to do stupid shit like that?!

@exile:
There is no way to get the same pointer or just exchanging the content. You can use the bitmap operations to make a copy of the bitmap, but this is going to be slow. What you should do is make your code able to deal with the changing pointer, eg. you could implement a notification system that allows potential listeners to listen for changes.