File -> Quit (Command-Q) missing about lximage-qt

[tsujan]

like with all other applications

I'm afraid you may haven't used an enough number of apps. Some call it Quit, some Exit and some Close, There's no issue to fix.

[probonopd]

Command-Q is missing.

Close closes a window.
Quit quits the whole application.

[tsujan]

The process of a single-instance app can be terminated when its last window is closed — or it can continue. There's no rule carved in stone; one can exit/quit/close a window or an app.

It seems you want to have a mac-like system. OK, it's a valid and personal preference. But please don't rationalize it as something that should be followed by all.

[stefonarch]

Ctrl+w for close/quit can be changed in Preferences → >Shortcuts.

Personally I've configured ctrl+q for "close window" in my window manager shortcuts settings to have the same behavior for all apps.
https://github.com/lxqt/lxqt/wiki/ConfigWindowManagers#keyboard-shortcuts