iphoto storage

Hi all, this has probably been asked and answered but i can find it. I was wondering how you can store your pics on iphoto without having 2 copies of the same photo taking up space on my hard drive. If i delete the photos from the "photo" tab all my events get deleted?

thank you

Unless you have your photos in the iPhoto library AND in another folder, you don't have two copies of each photo. iPhoto keeps the original photo in case you want to go back to it in the future and start your editing over. It keeps the modified version of photos you have modified. That's all. Unless you have duplicated them outside of iPhoto, there is only one original and maybe one modified in iPhoto itself. If you have them in another folder, you can delete the ones in there.