XnView Software

Hello.
In version MP, there is no option to scale the window to the image size simultaneously:
- small images should be displayed at their actual size;
- very large images should be scaled down so that they fit completely on the screen.
This setting is available in the classic version.

Welcome to the forums.

Evidently you have not tried all the settings available in Tools->Settings:View "Auto Zoom"

The Auto Zoom setting "Fit image to desktop" does exactly what you describe. Small images are displayed at 100% 1:1, and images larger than the screen are scaled down so that they fit on the screen, without distortion (no squeezing of aspect ratio), and the window size is adjusted to match.

If you are on an OS other than Windows and this option does not perform correctly, that is something the developer would need to address. But the setting works fine on Windows.