[Shotwell] create new version of photo

[Dougie Nisbet]

In f-spot it's possible to create multiple versions of a photo and then, 
if desired, detach a child image from its parent. This is handy for 
situations such as cropping, where I want to retain the original but 
also have cropped versions.

Is it possible to do something like this in shotwell? i.e. create a copy 
of a photo in the database.

Thanks,

Dougie