
In some cases, you might end up moving a number of photos to the trash in iPhoto (e.g. when using the Find Duplicates command), but then decide you don't want to delete the photos after all. Fortunately, it's not difficult to return photos from the iPhoto trash to the main section of the library. To do so:
Note that the "Put Back" command is mapped to the command-delete keyboard shortcut. One might think that selecting photos in the trash and pressing command-delete would delete them permanently, but it actually just moves the back into the library. The "Empty Trash" command is the only way to delete the photos permanently, and it will always delete all the photos that are in the trash - there is no way to delete just a subset of the photos that are in the trash.