I didn't vote because your ranges are too narrow. IMO, there should be between 10-20 pics for a hosted gallery, with the fewer being the better, but letting the design dictate the amount of pics. In other words, just make them look nice and appealing and the number of pics becomes less relevant. I have some with 17 pics, and some with 12.. I base how many on my main graphical theme's shape and size.
