There's no chat feature in Nuclino at the moment as most teams use it together with a chat tool like Slack. But we're planning to add some lightweight commenting soon.

Resizing a picture is not possible, but we're planning to add different size options like full-width vs. normal-width for each image. Would that solve what you're trying to achieve?

I was not sure if the board was more like a blank "powerpoint-like" space, or if it was more linear, thus my question about resizing.