How do I transfer my iPhone photos/videos to a NAS with afp-protocol? How do I transfer my iPhone photos/videos to my NAS?
I can connect to my NAS using afp-protocol.

My current solution is to mount the NAS on my MacBook using cmd-k in Finder, then by using Image Capture I can move them from the phone to the mounted NAS.

Is it possible to transfer directly from iPhone to NAS using afp, or do I need to go indirectly through my MacBook?

I use iPhone 5S with iOS 9 and I do have a MacBook Pro with Yosemite.
I was looking for this too. In Image Capture, I think you should be able to choose Import To: Other (if you scroll to the bottom of the choices there), and then choose your NAS storage location. At least I am able to do it that way. My NAS shows up on the left in the popup dialog similar to how it shows in Finder. Anyway I still prefer to copy to my computer first, and then to the NAS, so that I am sure I get all my photos without some error.