Fotón is a colloquial and fun way to say 'a great photo' or 'an epic pic'. It's formed by adding the augmentative suffix -ón to the word foto (photo), a common way in Spanish to express that something is large or impressive.
In this empowerment anthem, the line "Ella no subió una foto, ella subió un fotón" (She didn't post a photo, she posted an epic photo) highlights the character's post-breakup glow-up and confidence. It's a perfect example of modern, social media-era Spanish.
This is the ultimate post-breakup glow-up song! KAROL G tells the story of a woman who just ended a relationship, but instead of being sad, she's thriving. The song starts by saying they broke up again, "Pero esta vez no lloró" (But this time she didn't cry), which tells you this breakup is for real. She feels better without him, so she decides to get all dressed up and go out, specifically "pa' que el ex vea lo que se perdió" (so the ex can see what he lost). It's a classic revenge move, and it's so satisfying.
The song explains she was with this guy "desde los diecisiete" (since she was seventeen) and now she's in her twenties, a whole new person. She's not depressed; instead, her heart is in "modo avión" (airplane mode), and she's protecting it after learning to love herself. She's fully embracing her new single life, and when the DJ asks where the single ladies are, the song says "Ella fue la que más gritó" (She was the one who screamed the loudest). It's all about feeling confident and powerful after leaving a bad situation behind.