offline the hard drive containing the photographs is not connected or mounted so Aperture can have access to them, but, Aperture can see them if they are referenced images
managed images digital master located in Aperture Library. Aperture will back-up these master images using the vault
referenced images digital masters not located in the Aperture Library or managed images not connected to the Aperture Library. If the master images are not in the Aperture Library they will not be back-up using the vault you will have to do this yourself, but, Aperture will back-up the versions, metadata, previews associated with referenced masters
preview jpegs that are shared with iWork & iLife. Previews can be dragged & dropped into other applications. The cool thing about Previews is that you can view your photographs while they are offline
plug-ins third-party plug-ins are now supported in Aperture 1.5
edge sharpen controls for those of you who used the highpass filter in photoshop to sharpen photographs you will be familiar with the new edge controls. They work by lining the edges of contrasted areas within the photograph
© victor m maldonado