I joined the world for the first time as a .....gasp.... customer 
I've had some service department dealings since leaving the family business, but needed to buy a car for the woman. Holy shit did this experience teach me a few things that I never would have understood as a dealer. For one, all dealers I worked with are made to force a customer into their process. That part really sucks, but I get it and am planning to expand on this further. It has given me some excellent ideas for new product!
On the photo front both my girlfriend and I found 9 photos annoying. It was never enough and the photos always seemed rushed. I wanted to see if a car had specific features and you just can't figure that out with the limitation of 9. Personally I cannot tell you the right number of images, but I can tell you the cars where the photographer knew what to highlight were obvious.
For example: Fords are worth more when they have sunroofs. When there aren't photos of the sunroof all one can do is assume the dealer is greedy or the photographer was lazy. I know neither is the intent, but that was our perception....and I'm a 20+ year veteran who knows better!!!
My girlfriend, not being a veteran, was 100% opposed to submitting a lead or calling. She only wanted to make a visitation decision based on the photos. When the photos weren't there she gave a little bit of weight to the specs/options listed on the VDP. After watching her, her mom, her friends, and anyone else she shared cars with I am 1000000000% sold on the fact that photos make ups.
P.S. My girlfriend's family believes sending leads is a complete waste of time that just ends in relentless inbox hassling.