An app or script to watch folder and display new images in full screen?

Question

I'm teaching a photography class and would like to use a cheap setup to display photos taken by the students in real time.

I have a macbook pro and an iphone. I also have an eye-fi card but it's an old one and doesn't work with ad-hoc networks so that's out of the question.

I'll likely be using RemoteSnap on the iphone connected to an ad-hoc wi-fi created by the mac. With this setup, the photo jpgs end up in a folder.

How can I haev every new photo in this folder to appear on the screen (in full screen)?

Thank you!