Could a picture of a 1 year old naked on a potty put on a social network be considered child porn?

I have a niece who is 20 her Mother gave birth to her at 12. Well my niece gave birth at 19 to a little girl. Her mother was a horrible mother to her. Well it is a cycle..we had a horrible Mother growing up also.I basically had to raise all my siblings and my niece being our Mother wasn't around. Anyway she posted pics of herself with a g-string on and a bra, plus it was a backside shot. Then she posted a pic of her daughter on a potty naked. I was outraged. I have seen on many shows where people have taken pics to be developed of their kids in tubs. Then the authorities were called because they consider it child porn. You have to be careful what you do these days when it comes to pics of kids naked. I told her she needed to remove that pic of the child. She got mad and flew off the handle and took me off her friends list. That's fine but she needs to realize that I was looking out for her and that child! Was I wrong for telling her she needed to remove the childs pic?