How did you import from a recent iPhoto version?
The new version converted all of my photos to a default size of 360 x 270 and it's killing my entire collection.
iPhoto never will convert images on import - it has a non-destructive workflow and imports all image files as they are. Have you imported the whole library? Then you will now be seeing the thubnails and prewiews as additinal import. In that case delete all newly imported events and start over again.
To import an iPhoto Library into anaother library export the original master image files from the other library to a folder and import that folder into your iPhoto library. Or use iPhoto Library Manager to merge two iPhoto libraries into one, see: merge iphoto libraries with iphoto library manager
Regards
Léonie