I wrote a long post about my personal experiences with funerals. Cathartic, but more than anyone needs to know. Unless you're overwhelmed with services, leave it to the pastor — or whomever the church designates — to decide. But I would say that I would not expect the church to develop the slide show. (520 photos? Really? Let the funeral home take care of that; mine gave me a limit and I was glad, and glad to pay for the service.)
Funerals are an excellent opportunity to minister to the family and its friends. Don't spoil it by imposing rules, but don't let them take advantage. I was very aware that the people who were helping were exercising true Christian charity; they weren't "hired help." We were grateful they cared enough to offer whatever they could.
When someone wants too much, and considers it some kind of right, just say "We can't take care of that."