PC to Mac

Go to your Pictures Folder and find the iPhoto Library there. Right (or Control-) Click on the icon and select 'Show Package Contents'. A finder window will open with the Library exposed.

Look there for a Folder called 'Import' or 'Importing'.

Drag it to the Desktop. *Make no other changes*.

Start iPhoto. Does that help?

If it does then look inside that folder on your desktop. Does it contain anything you want? If not you can trash the folder.

Do not worry about what is in the iPhoto Library!

iPhoto makes thumbnails and some working duplicates. iPhoto knows about these and keeps track of them. These photos allow you to quickly view your photos and allows you to modify your images *without touching your original* if you decide that it was wrong to crop your ex out of every photo you have (don't ask) then a simple "revert to original" can restore the photo to its new-out-of-the-camera appearance.

While it takes some extra diskspace, it is a very sensible, conservative approach to image management that meets very many people's needs. The only folks that it does not work for are those who are obsessed with how the computer is storing their photos on the hard drive.

And don't worry about image degradation due to multiple jpeg encodings. iPhoto now has "non-destructive" editing, and always applies new changes to the original, so the modified file is always just one jpeg generation away from the original.