Hosting a folder for external access

I need to host a folder containing product images so that it can be accessible via the internet, for viewing purposes only. A website is not an option as there are close to 15,000 images which change on a weekly basis. Accessing the folder via VPN is also not an option, as per the clients requirements. He wants to be able to include links to the folder within emails. The folder is stored on a server running W2K3 SE. What would be the best way to accomplish this?