"Your picture illustrates my point. We have a photograph of a wave and if we use our imagination, we can see a shape that resembles a face. This is a totally different situation from a hand or computer drawn image in which a face is intentionally inserted."
The photograph of the wave proves that pareidolia effects can happen naturally and be missed by many until it is pointed out to them by an astute observer. Now combine this with the fact that Watchtower often creates its illustrations by using live models on a set, which the artist makes a likeness of. So if there happens to be a live set with a pareidolia effect which the artist is oblivious to, wouldn't he capture it in the image unwittingly? Just as many people can miss these so called subliminal images it is very plausible that the artists also unwittingly create them without noticing. So the argument about the artist knowing every stroke proves nothing. He can know every stroke and still be oblivious to the "subliminal image" - the pareidolia effect - that he unwittingly creates.
Look at it another way: What if the photograph posted by Africanman was the model used by a Watchtower artist to create an illustration, and as a result the illustration came out appearing to have a face? All the Watchtower subliminal image conspiracists would be hopping up and down about Watchtower inserting the subliminal image of a face in the illustration when, in actuality, the face was inserted by nature in the real world and the artist just did a very good likeness of the photograph and missed the effect.