As someone who has pointed out the crazy edits/angles/camera tricks she does, this is not one of them so I'd like to defend her on this. Boob asymmetry is pretty normal but there's other things piling up that makes her left breast look way bigger:
1: her right arm is back, stretching her right breast back as well which makes it smaller,
2: her left side is pretty close to the edge of the photo and since it's a wide angle lens, it distorts it almost as a fisheye lens. You can tell this is happening by looking at how thick her left arm looks, it's as thick as half of her torso. This is the same thing that makes her ass look bigger than what it is