Huh, that is true in both the model cards of Gemini 1.5 Pro and Gemini 1.0.
That feels like it runs counter to this statement from the Gemini 1.0 technical report[0]:
> Gemini models are trained to accommodate textual input interleaved with a wide variety of audio and visual inputs, such as natural images, charts, screenshots, PDFs, and videos, and they can produce text and image outputs