I need a system exactly like facebook´s photo tagging application:
Users click in a specific part of a picture and then indicates who that person is by selecting from his/her list of contacts. Users can also tag themselves or remove tags of their own user.
When users scroll their mouse over a tagged photo, the tagged person´s name should be displayed. A photo may have more than 1 tag.
A user should be able to visit another user´s profile and see all tagged photos of that user.
Users should also have the ability to specify if they want to moderate tags (authorize tags before they are posted) or allow anyone to tag them at any time. The network´s administrator should also have the ability to indicate if he allows users to select their own privacy settings.