how can i back up my photos from another device?

I had iphone 6+ it wasnt my type so i bought 5s and sell my 6+. In my 5s i sign in my apple ID Eveything was back up. My apps,contacts, recent calls and msgs. even the site that i browse. but my 2000+ photos only 400+ photos was back up and then it suddenly stop. So i went to settings ang turn on my icloud photo library. Then my 400+ photos disappear in my albums. I turn it off again but my photos doesnt showed up again my liBrary. I want to back up my 2000+ photos.