Simone:
If you select just the save as tiff checkbox then any edit you make in iPhoto whether it be a jpg or a raw file will have the modified file saved as a tiff file. The tiff file will be approximately 20 times the size of the jpg file.
If you're editing a jpg file to start with then there's no advantage to saving the modified file as a tiff file as the jpg compression has already been done of the file.
If you've checked the Use RAW when editing in an external editor you will have the option to select one of four formats: dng, tiff, jpg, psd. The edit has to be saved to a new file since the RAW file is never physically modified. If you're using PS or a 3rd party editor with iPhoto these tips might be of some help:
Using Photoshop (or Photoshop Elements) as Your Editor of Choice in iPhoto.
1 - select Photoshop as your editor of choice in iPhoto's General Preference Section's under the
"Edit photo:" menu.
2 - double click on the thumbnail in iPhoto to open it in Photoshop. When you're finished editing click on the Save button. If you immediately get the JPEG Options window make your selection (Baseline standard seems to be the most compatible jpeg format) and click on the OK button. Your done.
3 - however, if you get the navigation
window that indicates that PS wants to save it as a PS formatted file. You'll need to either select JPEG from the menu and save (top image) or click on the desktop in the Navigation window (bottom image) and save it to the desktop for importing as a new photo.
This method will let iPhoto know that the photo has been editied and will update the thumbnail file to reflect the edit..
NOTE: With Photoshop Elements 6 the Saving File preferences should be configured:
"On First Save: Save Over Current File". Also I suggest the Maximize PSD File Compatabilty be set to Always.
If you want to use both iPhoto's editing mode and PS without having to go back and forth to the Preference pane, once you've selected PS as your editor of choice, reset the Preferences back to "Open in main window". That will let you either edit in iPhoto (double click on the thumbnail) or in PS (Control-click on the thumbnail and seledt "Edit in external editor" in the Contextual menu). This way you get the best of both worlds
2 - double click on the thumbnail in iPhoto to open it in Photoshop. When you're finished editing click on the Save button. If you immediately get the JPEG Options window make your selection (Baseline standard seems to be the most compatible jpeg format) and click on the OK button. Your done.
3 - however, if you get the navigation
window that indicates that PS wants to save it as a PS formatted file. You'll need to either select JPEG from the menu and save (top image) or click on the desktop in the Navigation window (bottom image) and save it to the desktop for importing as a new photo.
This method will let iPhoto know that the photo has been editied and will update the thumbnail file to reflect the edit..
TIP:
For insurance against the iPhoto database corruption that many users have experienced I recommend making a backup copy of the Library6.iPhoto (iPhoto.Library for iPhoto 5 and earlier) database file and keep it current. If problems crop up where iPhoto suddenly can't see any photos or thinks there are no photos in the library, replacing the working Library6.iPhoto file with the backup will often get the library back. By keeping it current I mean backup after each import and/or any serious editing or work on books, slideshows, calendars, cards, etc. That insures that if a problem pops up and you do need to replace the database file, you'll retain all those efforts. It doesn't take long to make the backup and it's good insurance.
I've created an Automator workflow application (requires Tiger or later), iPhoto dB File Backup, that will copy the selected Library6.iPhoto file from your iPhoto Library folder to the Pictures folder, replacing any previous version of it. It's compatible with iPhoto 6 and 7 libraries and Tiger and Leopard. Just put the application in the Dock and click on it whenever you want to backup the dB file. iPhoto does not have to be closed to run the application, just idle. You can download it at Toad's Cellar. Be sure to read the Read Me pdf file.
Note: There's now an Automator backup application for iPhoto 5 that will work with Tiger or Leopard.
