Don't know how to get my pictures from my old iPhone on to my new one

I had an iPhone 4 in 2012, a few years later got an iPhone 5s. As soon as i plugged my computer into iTunes my iPhone took the same format as my 4s with all my photos, messages, contacts, and apps. I broke my iPhone 5s and had to get a new iPhone, same exact one, but when I plugged it into my itunes and connected with my cloud, none of my photos came back. I lost all of my photos. I just turned on iCloud Photo Library (Beta) and when it first started updating, it said it was uploading 4,000+ photos to my cloud. But now when I look at my cloud online, it shows only 700, only the photos that have been taken on this phone that i have right now. Where did my pictures go and how do I get them back.