You'd have to be stupid to take pictures of your naked body, send the film to a 2-day or mail-away photo lab, and not expect someone other than yourself to see your glory (or shame, as the case may be).
But you'd be an absolute idiot to send that same film to a 1-hour photo lab.
The tech who takes your film? She's probably the one who will actually stick her hands into the black box and pull your film out of its nifty little plastic canister to dip it in developer fluid. She will probably be the one who sticks the film into the machine, where it uses those film negatives to produce pictures in just a few short minutes. She will look through every single photo, checking that each one has developed properly into whatever it's supposed to look like. Anything that is all grey, or excessively blurry, etc., will be thrown away. She will see these nude photos. She will see the face (if there is one) that goes with the body. So when you come back to pick up those pictures, she will instantly know the most intimate details of your anatomy.
Furthermore, she knows who you are, has your name and phone number written on that little envelope you handed her, and have the rest of your info if you pay with plastic. She can track you down and stalk you if she really wants to. And heaven help you if your tech is a big burly dude who doesn't understand "boundaries."
And finally, in case you think that tech will be the only one to see the pictures and probably won't make a big deal out of it, I can assure you that the opposite is true. That tech will either keep the original photos and not give them to you at all, or print extra copies unbeknownst to you. The pictures will be kept in a special little box that is filled with the nude photos from other customers who've been so foolish in the past. These pictures will occasionally be passed around the store for all to see. If you're lucky, most of the store clerks will be like me and not want to see that raunchy crap, and will not look in the box. Unfortunately, for every clerk like me, there are five clerks who are not like me, and will at least give a cursory glance if not a full inspection of all the nude pics. Furthermore, store management will most likely occasionally take the box and empty it of its contents, to either be shredded or kept in the manager's private collection.
Trust me on this. You really don't want to get stares every time you walk into your favorite photo lab.
Author's note: My experience in this matter is limited to my previous employment at a Wal-Mart in the 1990s, when I was told it was store policy to confiscate and keep on file all nude photos processed in the one-hour lab. This was not told to me directly by a member of management, nor was I told if this policy held for all stores or only our own. I do not know what current policy is in effect. So don't sue me. I don't have money anyway.