Setting up a home network / central storage with Apple kit

[Cactussed]

Hi All

First up, I am a complete gumby with computer equipment, so lets start from that point.
At home, we have an imac, ipad, 2 macbooks and various iphones. And a Synology 2 bay NAS.

I have managed to get to the point where all my music is on the NAS (with auto backup) but everything else is on my imac (with the associated ilife software). I have managed to get my Sonos system to see my NAS so have access to all the itunes music from there as well as Spotify.

What I'd like to be able to achieve is having all my photos on there so they are automatically backed up also and also accessible from either the ipad or other devices. Also, ideally at more than a snails pace. Is this possible using any apple or third party software?

Some guidance would be much appreciated as I've done various searches and reading but found myself getting more confused.

[Cactussed]

Backup is OK, but what I want is a central place to store all my photos and documents then be able to access them from every device (a bit like a server I guess?)

[Cactussed]

Can I make iphoto use it or will that make a mess of things?
I've also looked in the directory and its all stored in an iphoto file, not as I would normally see on a PC?

Sorry if I am asking numpty questions