Shared photo library moving into new photos app? With the new app photos for mac, I'm getting a little confused. 
I didn't have that many photos in my iPhoto library, and yet it says that it is uploading 4000, where are those photos coming from? Are they coming from the shared photos in my shared photo stream? If so, how do I stop that from happening? 

Also, how do I sync the photos from my photo library on my phone, or is that what is already uploading? And I know that they sync between devices but do they sync screenshots and saved photos or only photos that are taken with the phones camera?
If you have Photostream turned on and set it to download Photostream photos, then iPhoto will put them in an Event by month. It will look similar to other photo Events that you've created. iCloud Photo Library sees these as just normal photos and will upload them. Everything in the System Library (which means the default Photos library) will get uploaded, so the only way to stop it is to turn off iCloud Photo Library or put those photos into a separate Photos library.

If you have iCloud Photo Library turned on in your Mac and iPhone, then they will eventually sync up.

All pictures in your iPhone Photos app will get uploaded into iCloud Photo Library (including screenshots and saved photos from other apps/internet).