Automatic window sizing's aspect ratio is incorrectly calculated, causing letterboxing
When opening a medium/large-size image from Nautilus with EOG, EOG almost always slightly miscalculates the window sizing, resulting in a viewport that never exactly matches the image's aspect ratio. For landscape images (ex: at 16:9 or 16:10 aspect ratio) this means you get letterboxing (empty/black bars) at the top and bottom, and for portrait images you get letterboxing on the left and right sides.
It would be pretty neat if EOG could do "perfect" calculation of the window size required to make the image fit flush with the geometry of the viewport, without letterboxing.
This affects version 45.x and every previous version. Tested with the Wayland version of GNOME Shell, without panel/dock-like extensions.