NK is really bad at photoshop...
Edges of the exhaust cloud are too sharp on the right near the top, too soft/blended on the lower left.
Sea surface too calm, no wave/spray from forcing the missile and gas bubble through it? Come on...
Exhaust cloud too dirty. Even if they were using an ugly gas generator... This looks like an exhaust and debris plume from a ground based launch.
Just what I see in 2 min, before coffee.