"fit to window" button in Toolbar

[I_go_r]

Hello!
I realy need a "fit to window" button on the Toolbar (near "zoom+" and "zoom-" buttons) because this is most often operation I use.
Please, please, please: make it possible to add it by customization or add it to standard Toolbar.
Thanks!!!
Because most of photos larger then window and every time I must go to sub-menu and select "fit image to window". This often operation and placing button in main toolbar will be very helpful.