Well I think picture writing is a notion that you can only understand if you trace back the actual history of the term.And the term comes out of attempts to give an account of the evolution of writing.
Now, start with the question, "Why was that ever important?" It was important, I think - as Ive said in print and various places - because it became one of the criteria by which modern Western societies rated themselves as superior to preliterate communities.
So the question then was as it were, "Well you know if we all start preliterate how does writing ever emerge?"
The simplistic answer is to look at what preliterate communities can do without writing. What preliterate communities can do without writing is draw what at least we would call pictures or even diagrams of things in order to convey information.
So if you grasp these two ends of the chain: it starts with pictures and somehow ends up with writing; then you've got to sketch out some kind of evolutionary link between these two. And picture writing is a notion that emerges just there as indeed the form of the expression tells you. It's something thats got somehow or other to link pictures to writing. And that job is given to it in advance of anybodys understanding how the process could possibly have happened.
So in one sense its from the start a con job concept. You know youve said: this has got to lead to that, so there must be an intermediate stage and well call that intermediate stage by an expression that links term A with term B. Once youve demythologized the concept of picture writing I cant see that theres anything to recuperate. In other words I then have to ask myself, Do I really have any grounds for thinking - once Ive realized the intellectual strategy involved - that there actually is a thing called picture writing which is somehow intermediate between A and B? And I cant see that I have any reason for thinking that at all. It seems to be a concept called into being by a misconception about the history of writing.
I dont know if that gives you an answer to your question but it certainly rationalizes my reluctance to look at things and say, Is this picture writing or not?