You have completely missed the metaphor. Let me break it down for you.
Everyone is not born as a good photographer. So people practice by taking many photos of various things, now all of them wont be good, some of them can be good but they probably wont be noticed by anyone but there will be that one photo which will be good and gets noticed by people that matter and they will pay a good amount for that photo.
So that 1 photo will make up for zero revenues from all the other photos. The 1000 photos is a metaphor, dont take it literally.
