Button to fit image to page

Greetings Opus aficionados!
I want to "Fit to page" using a shortcut key or menu item so I do not have to use the mouse.
One of the many fantastic things about Opus is I can customise my setup so that things I do often I can do easily with few keystrokes.
I have created buttons with hotkeys to rotate an image by 90 degress to the RHS/LHS example below

Image ROTATE=270 HERE REPLACE
@nodeselect

So now I want to do the same for "fit to page"
Really I am just copying these buttons which are located at the top of the image viewer:

They do not seem to be accessible like standard opus menus/buttons so I cannot go and edit them and copy their innards (Or can I ?????)

In order to "fit to page" I went to the image internal command thinking I would have to implement something similar to the rotate button shown above. But alas I can find no switch which would do the job!

Any hints greatly appreciated as always....

Do you actually need a button for this?

You might simply try Preferences > Viewer > Appearance > Standalone Viewer Appearance > Auto-size viewer window

That rotate command rotates the file itself, not just the image in the viewer pane, so it's not identical to the buttons at the top of the viewer pane.

The standalone viewer lets you use commands (and thus hotkeys) for fit to page etc. but I'm not sure the preview pane can be controlled in the same way at the moment.

@Chuck and @Leo - Thank you gentlemen...I will look into the autosize setting...