If you delete a photo from within iPhoto and then empty the trash within iPhoto it will be deleted from the iPhoto Library. If the photo exists elsewhere on your hard drive, flash drive, SD card or backup it won't be deleted from those locations by deleting it from within iPhoto. If you have it in locations other than iPhoto and want it deleted from those locations you'll have to find them and delete them separately.
I wondered this. So simple answer: if the photo was imported straight into iPhoto- yes; If the photo was copied to your drives first- no.
If you delete a photo from within iPhoto and then empty the trash within iPhoto it will be deleted from the iPhoto Library. If the photo exists elsewhere on your hard drive, flash drive, SD card or backup it won't be deleted from those locations by deleting it from within iPhoto. If you have it in locations other than iPhoto and want it deleted from those locations you'll have to find them and delete them separately.
I loaded photos from my External hard drive and simply drag and dropped to iPhoto. So if I delete it in iPhoto and simply empty my trash its deleted for good? Or is there some empty the trash exclusive to iPhoto if so I never saw it?!
That depends on your iPhoto settings. Open iPhoto preferences, then navigate to the "Advanced" tab and see if "Copy items to iPhoto Library" is checked. If it is, deleting in iPhoto will remove the copy that was imported. If not, only the reference to the photo is removed. In either case, if it existed somewhere on your machine before it was imported, it may still exist even after deleting in iPhoto.