If you're just serving photos and videos on your home network then you don't really need a full RAID setup. RAID has to spin up all of your disks on every access which is a waste of energy. And you can't access the data, in case of emergency, on a single disk outside the array. I'd use a JBOD setup with Snapraid for paraty. That has the advantage of being able to use different size disks.
Ian