I should be able to retrieve a disconnected Photo

(User Story, To be Fixed , Priority: Medium, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Photos
Summary: Especially because of Old editor loses photos, it is very easy currently to "orphan" a photo -- not deleting it, just winding up with nothing pointing to it. We should have a way to re-add an existing Photo to the Thing that it is for.
This probably implies that "Add Photo" should have a mechanism for selecting a photo from amongst the ones in this Space. This probably requires an additional permission; I suspect that this would default to either Contributor or Editor.