We all make mistakes, and that's certain to happen on occasion when you're working with your photos too. With digital photos, though, your changes aren't irrevocable.
Ways to undo changes to a photo:
After you've performed an action, to undo just that action, choose Undo from the Edit menu (). Keep choosing Undo to undo earlier actions.
To remove all changes from a photo, select it and choose Revert to Original from the Photos menu, or -click the image and choose Revert to Original from the contextual menu.
If you are in edit mode and have made at least one change, iPhoto removes all changes from the photo that were made that session. In any other situation, iPhoto warns that you'll lose all changes to the photo, and swaps in the original image (Figure 4.56).
Figure 4.56. To revert to the original version of an image after making a number of edits, select it and choose Revert to Original from the Photos menu. iPhoto warns you that you'll lose all your changes.
To revert to the original look of a photo while working in the Effects panel, click its Original button.
You can undo changes made in edit mode only until you save the changes to that photo.
To see what the photo would look like if you were to undo a change, press . You must still choose Undo if desired.
iPhoto modifies the Undo command in the Edit menu to reflect your last action.
Anything you can undo via the Undo command, you can redo via the Redo command in the Edit menu.
It turns out that Revert to Original isn't doing anything complicated. When you edit a photo, iPhoto makes a copy of the original in a folder named for the photo's film roll, stored in the Modified folder. As long as this happens, you can recover the original image no matter what edits you make to it.
In fact, this is why Revert to Original works even if you edit a photo in another programiPhoto starts tracking the original as soon as you double-click the photo. However, don't drag a photo from iPhoto to the Dock icon of another program to edit it; if you do so, iPhoto can't track the changes.
You can locate an original image in the Finder by -clicking it and choosing Show File (to find the original if unedited, or the modified version if it has been edited) or Show Original File (to find the original file if the photo has been edited).