Actually I think they look rather distinct.

The one from 4 years ago has a distinctly convex trailing edge. From all of my observations, the convex trailing edge in the presence of a broad base is extremely specific for chinook. They won't all have it, but if you see it, it's a king.

The more recent pic has more of the pointer finger configuration to the leading edge with a concave trailing edge. This pattern appears to be more common in coho.

Since the rest of that fish also screams coho.... I voted coho.