I know that's not exactly a tiny engagement ring but I think both the engagement ring (definitely looks like there's a separate wedding band) is still quite understated. The whole thing is lovely and simple and similar to my style but I just don't have the bank balance to get anything like that.
All in all, I think they look wonderfully happy and that's the important thing.
Here's the slideshow from Bahamas Weekly
Here's the photo from PerezHilton of the bands up close.