[Enhancement] Set default image (and thumbnail) fit option

[DanyGee]

Hi,
first of all THX for the new Image Viewer - its just soooo eye pleasing 😍

Please consider adding an option to set default fit option.
I personally would like to set it to fill/zoom so the image always takes the whole area of the window, just like in the example below:

And here's an example how it is now:

Same should apply to thumbnails ☝🏻 🧐
Stretched images/thumbnails give that unprofessional look.

Cheers 🍻 and looking forward to such enhancement!
Dan