Thunderbird bz 579023 still not fixed even though there is an upstream fix available

Kevin Kofler kevin.kofler at
Tue Apr 27 23:16:09 UTC 2010

Chris Tyler wrote:
> APNG was created to fill a void -- there was a need for a modern
> animated format with two qualities: it needed to be lightweight and
> backward-compatible (degrade gracefully). After nearly a year of
> discussion and consultation, the PNG group decided not to back it;

Because they already have a perfectly fine format, MNG, which Mozilla 
decided to drop support for. And in fact the main reason graceful 
degradation is needed at all is browsers not supporting the format. What do 
you suggest next? That all images need to "gracefully degrade" in a browser 
which only supports GIF, such as the original Mosaic? The fact that support 
for animations is being hacked into a format designed for still images is 
one of the complaints the PNG group had about APNG.

> Mozilla gave it further thought and decided they needed it. It has since
> been implemented by other browsers (such as Opera) and used in other
> applications (such as WorldDMB, see ESTI TS 101 499 V2.2.1).

That's 2 of the major browsers. Come back when you get M$, Google, Apple 
etc. to support it. Even MNG had wider support before Mozilla dropped it, 
e.g. Konqueror in KDE 3 supported it just fine. (Sadly, in KDE 4, support 
for animations in Konqueror regressed and MNG was one of the victims of it. 
Other problems include: "stop animations" initially didn't work, I fixed 
that; animated GIFs don't animate when resized, at least last I checked. But 
that's not a Mozilla issue.)

> The alternative, MNG, is a heavy spec that offers no graceful
> degradation for older browsers. It's been around for years, but is
> almost never used. If it was a lighter spec, surely we'd be using it for
> animated cursors and throbbers by now.

The main reason it's almost never used is lack of browser support. Mozilla 
dropping their existing support for it definitely did not help!

        Kevin Kofler

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