I have 2347 updates, also member Bonus sets too.  I would say over the years I 90% of my sets have close
to 100 photos and as many as 300 photos in set 300. That was way back when photos were posted a small size.
I still try to keep my sets on the larger number of pictures.  On free side I never put less then 12 photos.  What is a good
number in an update I have no idea.  I know I love to please my fans and members, many fans become members.
 Of course, the quality of the photos is very important too.
Hugs all  

 , Alexus Lin  

   Of course the quality of the photos is very important