The information pane

In the lower left corner of the window, you'll find the information pane, which will display detailed information about whatever object you have selected in the rest of the window. You can use this to see information for a library, album, event, or individual photo. The following information is displayed here:

For libraries: the library's name, iPhoto version, size, and location on your computer. The size shown is for the entire library package, including all of iPhoto’s own data files. Note that this size will be larger than the size shown in iPhoto itself, which only adds up the space taken up by the photos themselves.

For albums: the album's name and description, and the number and size of the photos it contains.

For events: the event's name, date, and description, and the number and size of the photos it contains.

For photos: all of the photo's attributes (name, date, rating, keywords, description, faces, place, kind, and size) as well as the full paths to both the original and modified versions of the image.