From Matt Sephton:
Digital cameras attach information to each photo you take. This information - called EXIF data - contains the time-stamp, aperture and shutter time amongst other things.
However some brands of cameras also attach a lot of (arguably) extraneous data. This is inconvenient for a number of reasons, but most of all the fact that iPhoto caches all this data in it's Library file resulting in slower operation after each new import of photos. Affected camera brands include: Casio, Konica Minolta, Kyocera, Nikon and Pentax - amongst others.
This application will seamlessly clean your photos of extraneous exif data prior to importing into iPhoto.