tool for users to post photos

I have an application where about 100 individuals will be submitting photos. I would like an automatic way for them to send the pictures, have them automatically loaded into Gallery and reduced in size to save space. I would have a convention where we store the photos by email address or something similar.

My users can send email and follow a simple application. Most can upload files, but ask them any questions they will just give up.

With such a rich collection of ad-ons I don't know where to start.

Thanks for any advice.

Bruce