Why is iPhoto 11 not recognizing already imported photos from 4S?

I just plugged my 4S into my iMac i3, which is running OSX 10.8.2 and iPhoto 11' all products are up to date on software updates. I wanted to removed some videos off my 4S to free of some space on the phone. I normall use icloud for all photo syncing and what not so plugging my 4S into the imac is not a common thing for me.

After opening iPhoto I noticed that the photos that were selected as "New Photos" were most duplicates of older photos that were already in my iPhoto library, some dating back a couple of years ago. I keep copies of them on my iphone to show people when I'm away from my imac. What I don't understand is why is iPhoto thinking these are "New Photos" and not "Already Imported" photos? What is even stranger is that when I look in the "Already Imported" photos, those same photos (the ones that iPhoto wants to now import again) are showing up there too.

So my dilema is, that iPhoto is saying that out of 1,289 photos on my 4S, 354 are "New Photos" to be imported but about 250-300 of those are NOT new, they already exist in my iPhoto library. Why is iPhoto not reconizing already imported photos?

Also, if I am using Photo Stream to sync my photos across everything.. why do I even have any new photos to import?? Shouldn't everything already be there when I open up iPhoto, why would I need to import any photos from my 4S if icloud and Photo Stream work correctly with iPhoto 11' ? I have checked and made sure numberous times that I have Photo Stream and icloud turned on in all the correct places and devices.

What I'm currently using: iPhone 4S iOS 6.0.1 and iMac i3 OSX 10.8.2 and iPhoto 11' version 9.4.2