I just discovered this collection of photographs on the Stanford Medical School Newborn Nursery website. It has pictures of things that are common and uncommon, of concern and not. It has pictures of mature breastmilk, green expressed milk (not a problem by the way), baby poop, tongue-tie, and many other things. This looks like a handy resource.
Yes, it’s a fabulous resource!! Good video on clipping a tongue-tie, too.