Yes!!
Is it a crime if someone uploads nude pictures of a woman without her consent?
It is an attack on a person's well being and character and privacy. It could constitute the person that did it as trying to defame, abuse, harass, stalk, threaten or otherwise violate the legal rights (such as rights of privacy and publicity) of others and could have severe legal actions or lawsuit against that individual who did it. That persons image is protected under United States Copyright Act because her self image belongs to her and posting it is a violation of her rights. She has legal grounds.
Yes it is .
Yeah, it's illegal. You'd likely get sued for it.