I think Wordpress is definitely your best answer and I would be glad to show you how easy it is.

Photo Gallery - Photographers can easily upload their work:

With a few Wordpress plugins (which are easy to use), there are plenty of photo galleries out there for your photographers.

Photographers selling their work:

I can show you how to add a simply ecommerce plugin on Wordpress to easily help the photographers sell their work online.

I would love to show you how on a call.

Bruce