How to reduce space between tiles (image view)

Don't know if it is possible, but if it is, where to look to change the white space between thumbnails / tiles in case of image view. I checked:
Preferences->File Display Modes->Thumbnails: spacing is 0 x 0
and under Tiles I reduced the spacing to 8x3 pixels, but see no result.
Or maybe it is already set to a minimum?

Background: sometimes I wish to reorder a folder manually. Opus is set to image view.
The images are having a date printed on them. The thumbnails need to be sufficiently large to read the date, so I can sort them on date. For that purpose I'd like to have as many images as possible on screen. Noticed quite some white space.
BTW - a note: in this scenario, when moving an image to an off-screen point, the scrolling isn't 'smooth', meaning to say that when I go somewhere very close to the top of the right window panel, Opus does not scroll slowly to the next upper row, but 'jumps' too far and I have to go back and forth to get to the right row/position.

2019-06-14_12-57-28

The thumbnail size setting plays a part. It's usually square, which means landscape rectangular thumbnails will have empty space above them. You can make the size rectangular if most of your images are like that, to reduce the extra space.

Thanks. Indeed in this case it was set to 435x435. I changed that to 435x320 saving quite a lot of white space. Untagged the square thing.
Thanks again.