It's great. This shot is helped by the tight bikini. See how the side string pinching into the "booty meat" aka glutes?
This allows said "booty meat" to "bubble up". So, you take that pic at the right time, and good angle. It's akin to the "arms-crossed-and-pushing-hands against-biceps-to-make-them-larger" pose, except this is done by the clothing.
You see this a lot in those candid Brazilian pics, the tight bikini sides/strings pinching into the butt.
Yeah, butt them back dimples, though.