All modern models are processing images internally within its own neural network, they don't delegate it to some other/ocr model. Image data flows through the same paths as text, what do you mean by "quite limited" here?

Your first comment was refering to unconscious, now you don't mention it.

Regarding "conscious and linguistic" which you seem to be touching on now, taking aside multimodality - text itself is way richer for llms than for humans. Trivial example may be ie. mermaid diagram which describes some complex topology, svg which describes some complex vector graphic or complex program or web application - all are textual but to understand and create them model must operate in non linguistic domains.

Even pure text-to-text models have ability to operate in other than linguistic domains, but they are not text-to-text only, they can ingest images directly as well.