I use iPhoto and up to now have done most simple manipulation direectly in iPhoto. I just got Photoshop CS4 and want to use PS for more advanced editting. So, say I have a photo in iPhot that I want to edit. What steps do I need to take? Do I export to the desktop, then open in PS and edit, save back to the desktop, then re-import to iPhoto? What about the version (original) already in iPhoto?