Sooo... i found a high school classmate of mine in r/gonewild, should I tell her, or keep it as my secret?

obviously this is a throwaway account, and I'm not going to link her r/gonewild post to respect her privacy. Let me know what I should do, tell her, if so, how should I go about it, or keep it to myself and let it eat away at my soul? If it helps in the decision making, I had a class with her my senior year and was one of the few people I liked talking to in that class, never really talked outside of school though. also frequents to the pool I work at....