She is standing with her shoulders hunched because there is a stream of water landing on her, so her breasts appear to be hanging lower.
The camera is low and close and has quite a wide angle lens. Not crazy-wide, but still wide. Compare the apparent size of the tiles behind her with those on the left of the shot. The tiles are the same size but those on the left look twice as big.
Sure, her breasts are very big, but what's the point of fantasising about their being bigger than they really are?