You should ideally have pictures from different times, events, places, etc. Sending in 50+ pictures of the wedding alone is not going to help, so it's best to have different pictures from different stages in your relationship. Some VOs ask for pictures of the different ceremonies in the wedding.
Duplicate photos means pictures that show the same people in the same place. So sending 5 pictures of you in the same place won't help.
Do the best with what you have for proof. If you don't have it, then you don't have it.