According to a post from NASA, the bright clouds featured in the image are "most likely ammonia or ammonia and water, mixed with a sprinkling of unknown chemical ingredients":In general, the darker cloud material is deeper in Jupiter's atmosphere, while bright cloud material is high. The bright clouds are most likely ammonia or ammonia and water, mixed with a sprinkling of unknown chemical ingredients. However, with JunoCam we can observe the fine-scale structure within this weather system, including additional structures within it. There is not significant motion apparent in the interior of this feature; like the Great Red Spot, its winds probably slows down greatly toward the center. The raw images from Juno can be viewed via NASA's JunoCam web portal.