Looking for a plugin to let site visitors save photos to their own "lightbox" or "favorites" list

I'm not talking about using a lightbox plugin that makes images pop-up. Because all those hundreds of plugins are called Lightbox ______ it's hard to find anything about what I'm really wanting to do.

I want to let visitors to be able to save photos to a "lightbox" like on a stock photos site. I'm working on a photography portfolio theme right now and the client wants to let visitors pick their favorites and send an email to themselves or him with that list.

The graphpaperpress Sell Photos theme (http://graphpaperpress.com/themes/sell-photos/) has a similar feature, but it's all tied to their Sell Media plugin and the rest of the way it's set up is way too complex for what I need.

Any ideas for how best to pull this off or any other plugins you've used that could help?