FVWM: Full crash when using an invalid PNG for a mini-icon

Hi All,

I'm using fvwm 2.6.7 from Debian/stretch.

If I execute the command

    Pick WindowStyle MiniIcon password.png

I get a full FVWM crash (and consequently an X server exit + lost work +
tears).

The problem is that the png file password.png (which I'm attaching,
and hoping it makes it past the list mail filters) is badly formed. When
opening it, libpng reports an error:

    libpng error: IDAT: invalid distance too far back

Regardless of what the error with the PNG is, FVWM should just install a
Dummy MiniIcon (or ignore the request) instead of crashing.

Please let me know if someone else can reproduce the problem, and if it
persists with the latest release. (I'm happy to file a bug report
instead if you prefer.)

Thanks,

GI

-- 
'Committee' -- A cul-de-sac down which ideas are lured and then quietly
strangled.