A PNG anti-aliased in transparent

To create an image like goo.png below, using Jasc Paint Shop Pro:

Create a new image, with 16.7M colours and a transparent background.
Draw on it in black. For this example, I used a black airbrush.
Mask – New – From Image: Source Opacity selected, Invert data off.
Mask – Save to Alpha Channel – OK – OK
The channel is called "Selection #0".
Save as .png, called foo.png. It saves it, with a warning to which I say OK.
Load it again. Paint all over it in black (this does not affect the alpha channel.)
Save it again, this time as goo.png.

works with

Netscape 4 No PNG background is black instead of transparent
Mozilla Yes thanks to the help of Greg Roelof and others
Netscape 6 Yes thanks to the help of Greg Roelof and others
Internet Explorer 6 No PNG background is grey instead of transparent
Internet Explorer 7 Yes
Opera 5 No PNG background is white instead of transparent
Opera 6 Yes

foo.png, anti-aliased in white
goo.png, anti-aliased in transparent

To see how smoothly the anti-aliasing of the
right-hand "G" image works, resize your browser
window, and change its width continuously.

Main index

works with
Netscape 4	No	PNG background is black instead of transparent
Mozilla	Yes	thanks to the help of Greg Roelof and others
Netscape 6	Yes	thanks to the help of Greg Roelof and others
Internet Explorer 6	No	PNG background is grey instead of transparent
Internet Explorer 7	Yes
Opera 5	No	PNG background is white instead of transparent
Opera 6	Yes

foo.png, anti-aliased in white	goo.png, anti-aliased in transparent
To see how smoothly the anti-aliasing of the right-hand "G" image works, resize your browser window, and change its width continuously.