She is engaging in full-on trolling in this prom picture.
It is crucial to be mindful of one's surroundings before capturing a photograph, particularly when considering its potential online posting. Regrettably, some individuals fail to recognize this until it is too late, creating amusing (and sometimes embarrassing) pictures.
In this instance, a group of girls is capturing an extraordinary prom photo. However, one individual disregards the significance of the moment entirely. Instead, they playfully prank their sister by having a photo taken while indulging in a bag of Doritos. Surprisingly, the photobomber steals the spotlight, overshadowing the beauty of the girls in the foreground.