The documentation give clear instructions for installing and setting up a Lemmy instance, but it doesn’t really tell me what I need to do so beyond the implication that I need some computer running Linux.
I have a QNAP NAS device which is running a flavor of linux; how much storage space is recommended for a public instance? Do I need my own website?
You need a domain as well. Not much storage space is needed, 50gb is plenty.
If I were to create Communities around art/photography, am I correct to assume that all those image files would be living on my instance’s storage?
You are correct - it will live on the instance it is uploaded to and federate out to instances subbed to it