Thank you for your question, Prof. Hua-kuei Ho.
I think my answer at the time of the presentation was insufficient, so I would like to make up for it.
If I understood correctly, you asked me how the ratio of the original or the imitation relates to the meaning of the verb "be (einai)."
I consider proportions to be such as a structure of a complex formed by its components.
And I think that everything that "is" is complex having both its own nature (or essence) and many other properties.
So then, in my presentation, the original model's proportion shows its nature (to on1) and current properties (to on2).
On the other hand, as I believe, an image's proportion indicates its original model’s state at a certain moment.
For example, a picture indicates its model and combines some colors or lines with this model.
Another example can be founded in statements (logos).
Its subject (onoma) indicates something that is, and then its predicate (rhēma) combines some properties with this subject.
Therefore, I think that image's proportion makes truth or falsehood in relation to its original.
Thank you again for your question, and I hope my answer has made my position clearer.