New iphone - how to do one way transfer?

So, old iphone (64gb) all backed up on iMac and iCloud. Full to the brim - mostly with photos.

New iphone (64Gb) received, which I want to connect to the iCloud, but I don't want all those old photos on my new iphone.

Ideally I'd like to have iCloud be my cloud based storage and leave everything there while I start to fill up the new iphone and have those new images sync to iCould. Doesn't appear to be possible so I'm looking for solutions.

Ideally I'd like a way to get all those photos off my old iphone and backed up nicely on several hard disks and an cloud based solution. It doesn't seem like the iTunes Backup solution allows for any kind of file level access? Unless you use other tools? Alternatively I can purchase another photo application (such as aperture) and it will allow me to backup. Is there not a simpler way to just copy the photos from my iphone onto my iMac?