How to sync different photo libraries from different apple devices used with the same ID
Basically, I have two iphones (4 and 5s). Both iphones are synced in Itunes as regards apps, music and all documents but for photos.
Each iphone has different photos, being neither of both libraries synced to Itunes or my pc. The problem is that when I bought the Iphone 5s and I tried to sync also the photos from the iphone 4 to later have them synched to the brand new iphone 5s, Itunes was not able to just copy the photos from the iphone into the pc, but rather copying the pictures from the PC into the iphone 4, removing all existing photos.
Also, icloud could not be used because I have more than 5gbs in photos.
Now the problem is that i got a new Ipad, and I would like to got into my ipad all the pictures from my iphone 4 and iphone 5s. Again icloud is not enough due to the 5gb limit.
How could i proceeed to merge both libraries and have them successfully synced in all my devices?
Thank you very much in advance