Bild, Darstellung (TLP 2.0251)

What is the isomorphy between a sentence and the world it describes?

Looking at the photograph, and assuming the world was similar to what we see in it—let us say we hold the photograph up to the scene it depicts—it makes clear sense to claim that the fork is to the left of the plate which has a trout on it: the picture indeed has the same logical form, and this is evident to everyone with normally working sight, who knows what to look for in a picture. (One may want to read Wollheim on what this entails).

Is it in any way like this with regard to the sentence:
"The fork is to the left of the plate which has a trout on it"
Surely, the word “trout” in the sentence is not placed on top of the word “plate”, even though “fork” is to the left of “plate”. And, we could have said, equally truly:
"The plate which has a trout on it is to the right of the fork"
which has the word “plate” to the left of “fork”.

I am sure what Wittgenstein is after is something logicians would make of the two latter sentences, abstracting from the contingent discursive form the sentences take.
(Discussion: But my point is, exactly, that the appearance of the picture is not similarly contingent to what it depicts, and Wittgenstein, in my view, is playing a rhetorical trick on us: he has us start off by referring to things that seem evident to all (a picture’s resemblance to what it depicts could be called an isomorphism between the two), to lure us into accepting that the same will hold between a sentence and the world).

Something like:
xF(y)
fork Left(plate)

But what work is this doing?
I think what Wittgenstein says is: let us call this evident thing of similarity differently so as to be able to have it wherever we represent something (hence: “The spatial image [“Bild” should be translated more neutrally (i.e. without the epistemological claims of x depicts y) “image”] everything spatial, the colourful everything coloured.” (2.171).)
But surely there is no way the sentences, let alone their logical formula, could provide the type of detail provided by the picture.

1. Is this what I am missing: “form” is a nominal term, not to be confused with the forms of the things as they present themselves to perception. (2.0141, which uses the ambiguous term “Vorkommen”). And what about 2.0251 (“Raum, Zeit und Farbe (Färbigkeit) sind Formen der Gegenstände.”)?
But then, why add the term “logical”? Is that just to make sure everybody understands what he is referring to? Okay, so now I do (I guess).
I still maintain that his use of “Bild” is misleading.

2. Wittgenstein seems here to be saying that it is not the perceptual aspect of pictures that makes them depict something—but see the other entry: I am not sure he is making that point in the right way.

Gerwen, Rob van. 1999. “Representaties waarnemen.” Feit & fictie IV:67–80.
Wollheim, Richard. 1993. “Pictures and Language.” In The Mind and its Depths, 185–192. Cambridge (Mass.), London (England): Harvard University Press.
____________. 2001. “On Pictorial Representation.” In Richard Wollheim on the Art of Painting. Art as Representation and Expression, edited by Rob van Gerwen, 13–27. Cambridge, New York: Cambridge University Press.