I agree with the guesses. 20" and 5lbs.
What strikes me is the mouth size. Usually when you get a 20 incher, you can fit your fist in their mouth, yet on this one, the picture makes it look like the mouth is full with just your thumb in it.
Without seeing the girth of the fish, I'd have to say around 19 inches, 4-5 pounds. Could be bigger/longer, though. Either way, it is a great catch. Had to be a lot of fun in kayak.