We start with a woman who says a diet company stole her personal weight loss photos to sell its products, turning her before and after shots into ads. She's fighting back. And abc's reena ninan has... See More
We start with a woman who says a diet company stole her personal weight loss photos to sell its products, turning her before and after shots into ads. She's fighting back. And abc's reena ninan has the story. Reporter: Ronny nunn went from extra large to medium. Trying everything. I did the grapefruit diet. I did atkins, and low-carb. Fasting and the cabbage soup diet. Reporter: Losing 75 pounds the old-fashioned way, diet and exercise. I started a blog. And I committed to journaling my thoughts and feelings, regardless if I was losing or gaining. Reporter: Posting a photo of herself every month to document the transformation. She was shocked when her photos were used to promote diet products. In one ad, called jess. This ad says the weight that took a full year to lose came off in just 30 days. It's scary to think that someone would try to sell something that has no grain of truth. Reporter: Internet security experts say this isn't an isolated case. Even kate middleton's images were used without her consent to plug diet products. It's not just the princesses of the world or the famous celebrities of the world. You're going to find that people are doing this to the commonfolk like ourselves. Reporter: Ronny had difficulty tracking down the companies using her images. A mailing address abc news found for one of them, turned out to be a p.O. Box in florida. Ronny has sent cease and desist letters to the e-mail addresses she obtained. It's taken down for 24 hours. Then pops up somewhere else. Reporter: She is asking people to repost her weight loss story. And reminding everyone -- I don't think it's possible to sell weight loss in a bottle. All of that hard work. Congratulations to her. Absolutely.
This transcript has been automatically generated and may not be 100% accurate.