I've seen Ariel from the little mermaid in a green dress on posters and other things yet in the movie she never wears a green dress...when did she wear this dress? In part 2?? Or where did it come from?

I think that it was also used because that is the color of her fins when she was a mermaid.

Disney gave them makeovers earlier this year and it caused some controversy.
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This look is for the merchandise. We already talked about this and even did polls on which redesign was better here on fanpop. Some people hate them and some people like them. I'm one of the people who likes them, especially Ariel's. Ariel's redesign was voted the best redesign in the polls we did here on fanpop. Someone here did an article about the details in the redesigns.