On my MacBook, with 10.7.3, if I go to
~/Pictures/iPhotoLibrary, no images show in the Finder, though it does say "size 4.01GB". If I double click on iPhotoLibrary, iPhoto opens up — is this the only way to view images and drag files, etc? Can't I view them in Finder?
The iPhoto (and Aperture) library is now a package — it's still a folder on disk, but in order to view its contents, you must explicitly choose File > Show Package Contents in Finder (or you can right-click on it).