On Sat, 24 Aug 2019 19:17:31 +0900,
Eli Zaretskii wrote:
> 
> > Date: Sat, 24 Aug 2019 18:01:46 +0900
> > From: mituharu@math.s.chiba-u.ac.jp
> > Cc: 37153@debbugs.gnu.org, Paul Eggert <eggert@cs.ucla.edu>
> > 
> > I suspect there is a longstanding typo (or thinko) in PNG
> > transparency handling code.
> > 
> > 				     YAMAMOTO Mitsuharu
> > 				mituharu@math.s.chiba-u.ac.jp
> > 
> > diff --git a/src/image.c b/src/image.c
> > index 81d8cb4e2b2..819e058f7e1 100644
> > --- a/src/image.c
> > +++ b/src/image.c
> > @@ -6680,7 +6680,7 @@ png_load_body (struct frame *f, struct image *img,
> > struct png_load_context *c)
> >    /* Create an image and pixmap serving as mask if the PNG image
> >       contains an alpha channel.  */
> >    if (channels == 4
> > -      && !transparent_p
> > +      && transparent_p
> >        && !image_create_x_image_and_pixmap (f, img, width, height, 1,
> >  					   &mask_img, 1))
> >      {
> > 
> 
> That didn't change anything in how I see the image in question, FWIW.

Attached is a screenshot on X11.  Probably W32 needs some more work.

				     YAMAMOTO Mitsuharu
				mituharu@math.s.chiba-u.ac.jp