How do I batch import user photos?

I have 300 people I want to import into my membership site. I also have their pictures. How do I import their pictures along with their other info such as name, email and some custom fields?

I plan to import them into Google contacts first. I am not sure if I need to import into Google Contacts.

What is the best way to import new users and include their photos/avatars?

Should I use Gravatar? Should I ask all of my students/users to get a gravatar first?