Version 4.52
I find that when running a slideshow of images, many of the numeric hotkeys behave differently from what is shown in the list in Options > Properties/Settings > Full screen / Slideshow.
In my testing, only number 4 functions as stated

1 - fits large images to screen [list says show images original size]
2 - fits all images to screen [list says fit large images to screen]
3 - stretches all images to screen [list says fit all images to screen]
4 - stretches all images to screen [list says stretch all images to screen]
5 - stretches all images to screen [list says fit image width to screen]
6 - stretches all images to screen [list says fit image height to screen]
7 - stretches all images to screen [list says fit small image side to screen]

Does that count as a bug?