How can I see pictures not imported using iphoto within iphoto?

Question

I just got a new iMac and am converting over from a Dell PC.  I have thousands of pictures that I copied over.  I then synced my ipad and all those pictures imported using iPhoto.  I liked the ability to see Events and Faces and ws thinking I might like to bring in all of my older pictures.  Is there a way to do that? Would I even want to? Would it recognize the folder structure I established for each event? 

Answer 1

As Léonie pointed out each folder imported into iPhoto will result in an Event with the same name as the folder. In the photos mode with Event titles set to be displayed you'll get this:
Once inside iPhoto you can merge  Events or drag photos from one event into another.
However if you want to create a hierarchical folder organization you'll need to do that in the left hand pane of iPhoto with folders and albums. 
That is create a folder and drag events into it and you will have albums in the folder representing the events.  These are only pointers to the original files and not duplicate files.  Folders can hold folders, albums, books, slideshows but not individual photos.  So you could create a hierarchy like this:
OT