The reason for calling the post office whether registered or not, is to find out if the system is running slow. I agree also that being in Southern NJ I am sure it is extremely slow! In fact dont they have to clean everything? While that happens doesnt the mail stop being processed? My husband also said that sometimes depending on what part of the country you are sending the mail to, it can be sent to a third location where it is sorted, and then passed on to another state. For instance, all of Utahs mail is sent to Idaho before it ever makes it to Utah, and thats just because of the large scale plant in Idaho. Like I said before, if there isnt anything within a couple of weeks, I would call the post office first and find out if the mail was delayed. That will give you an idea on how long to wait on Snapfish.
Good luck! We lost the very last family gathering pictures of our family once, with four generations, and they were taken by professionals who lost them!