Why can't I see my photos out of this App?? What could I do?

Hi, everyone!

All my photos are on iPhoto, but I can't see any folder with them out of the iPhoto!

So..... When Im on twitter, FOR EXAMPLE, and I want to put a pic as Profile Photo, I have to copy the photo from iPhoto to any folder (desk, example..) then, I open the twitter photo searcher to pick up that photo and upload to the site.... Is it right?? I thought I could search the pics in some folder created automatically by iPhoto in the IMAGES folder..... =/ ........Sorry for my English. This is not my native language.

Thanks....