App Icon if Style Icon & MiniIcon are not set

If I set a style (Icon and MiniIcon) for each application, minimized apps have the icon size I want in IconBox, as well miniicons in TitleBar and FvwmPager.
But if I don’t set the style, the minimized apps icons don’t have the same size. Some are larger some smaller.
Is there a way to set the icon size for minimized apps?
And, how do I find out if the application doesn’t have an icon.

Style * IconBox $[fvwm_iconbox_geometry], IconFill left bottom, IconGrid 10 10, IconSize 32 32 Style "*" Icon apps/32x32/gentoo.png, MiniIcon apps/16x16/gentoo.png, PositionPlacement Center, SkipMapping

IconSize will do it.

– Thomas Adam

Fvwm manual for IconSize:

Yes – of course. That’s why you need to provide one.

– Thomas Adam

I understand now, IconSize don’t resize icons, if I want a 32x32 icon I must set a 32x32 icon for Style Icon.

But then I have to set an icon for each application I install/use.
So I want to set the icon when application starts.

*FvwmEvent: add_window  "ThisWindow (!FvwmPager, !FvwmScript) WindowStyle Icon $[w.resource].png, IconOverride"

Doesn’t work, $[w.resource] is single-quoted, I get ‘myapp’.png.

Yes, that’s right. It is documented to work that way.

– Thomas Adam