Failing for me on Chrome today. I see a new window with a little gif in it.
This PNG is the primary means by which I share the schema diagram with my customers. Please fix!
A workaround is to load the diagram in Firefox. While you can't _edit_ it there (Firefox isn't supported for editing), you can _view_ it there. In the view mode, there is a "PNG" button and it works!
Customer support service by UserEcho