Only registered peoples allowed to upload

Hello,
I’m starting using Contest Gallery. Almost everything I need. Just one issue : I have created a gallery and right now, everybody can upload pictures. I would like that only registerd members of my photo club are able to upload pictures. Is there a way to automaticaly switch to the login page in case someone that is not logged nor registered, wants to upload a photo ?
Many thanks in advanvce.
Greetings from France.