Is it possible to add an item in Options\fullscreen\Show Information\Insert>>: "image size ratio" (4/3=1.33; 3/2=1.5; etc...).
This value is already calculated see here (1.25) :
And Harmonize all Tag items between "Options\fullscreen\Show Information\Insert" and "Slide Show\More Options\Show information\Insert"
(for example: zoom tag, etc...)